DeepSeek Not Working? An Advanced Troubleshooting Flow (Web + App + API)

Before changing your browser, app, API key, model ID, or code, check our DeepSeek status guide and then confirm any outage on the official DeepSeek status page.

Quick answer: If DeepSeek is not working, diagnose the issue in layers: official status, local browser or app, network and DNS, account login, API key, balance, request body, current model ID, rate limiting, and upstream service health. For API users, the current official model IDs are deepseek-v4-flash and deepseek-v4-pro. Do not treat deepseek-chat or deepseek-reasoner as primary current model IDs in new troubleshooting examples.

Independent note: Chat-Deep.ai is an independent DeepSeek guide and browser access site. It is not affiliated with DeepSeek, DeepSeek.com, the official DeepSeek app, or the official DeepSeek developer platform. For account access, billing, API keys, official privacy terms, and production-critical API information, use official DeepSeek resources.

Last verified: April 24, 2026.

Current DeepSeek API snapshot for troubleshooting

• Current API model IDs: deepseek-v4-flash and deepseek-v4-pro
• Base URL for OpenAI-compatible API requests: https://api.deepseek.com
• Current API generation: DeepSeek-V4 Preview
• Context length: 1M tokens
• Maximum output: 384K tokens
• Thinking mode: supported on both current V4 API models
• JSON Output and Tool Calls: supported on both current V4 API models
• Legacy aliases: deepseek-chat and deepseek-reasoner currently route to deepseek-v4-flash non-thinking and thinking modes
• Legacy alias retirement: DeepSeek says deepseek-chat and deepseek-reasoner will be retired after July 24, 2026, 15:59 UTC

This guide is updated to match the current Chat-Deep.ai homepage, DeepSeek API guide, DeepSeek pricing guide, DeepSeek token usage guide, DeepSeek Thinking Mode guide, and DeepSeek Tool Calls guide.

Quick diagnosis: why is DeepSeek not working?

If you need a fast starting point, check these first:

• Status: Check the official DeepSeek status page for API or web chat incidents.
• Browser/app: Try a private browser window, another browser, or the official app.
• Network: Try another network, mobile hotspot, or DNS route.
• Login: Confirm that you can sign in to the official DeepSeek website or app.
• API key: Confirm the key is valid and sent as Authorization: Bearer YOUR_API_KEY.
• Balance: If you get a 402 error, check your official DeepSeek platform balance.
• Model ID: Use deepseek-v4-flash or deepseek-v4-pro in new API calls.
• Request format: Confirm your JSON body includes model and messages in the correct shape.
• Rate/concurrency: If you get 429, slow down requests and use backoff.

If these checks do not identify the issue, continue through the layered troubleshooting flow below.

Table of contents

• Quick diagnosis
• How to diagnose DeepSeek issues systematically
• Layer 1 — Browser, app, and device
• Layer 2 — Network, DNS, proxy, and firewall
• Layer 3 — Login, API key, and balance
• Layer 4 — Request body, model ID, and V4 configuration
• Common DeepSeek API error codes
• Layer 5 — Rate limits, concurrency, timeouts, and keep-alives
• Layer 6 — Official status and upstream incidents
• Web and app-specific troubleshooting
• Minimal API debug checklist
• Current V4 model troubleshooting
• Legacy aliases and migration problems
• FAQ
• Official sources

How to diagnose DeepSeek issues systematically

When DeepSeek is not working, do not guess. Move through the system one layer at a time. A failure can come from your browser, device, app installation, internet connection, DNS, proxy, API key, account balance, request format, model ID, concurrency, or an upstream DeepSeek incident.

Layer	What to check	Common symptom
1	Browser, app, device, cache, extensions	DeepSeek works on another device or browser
2	Network, DNS, VPN, proxy, firewall	DeepSeek does not load or API requests time out
3	Login, API key, balance, account status	401, 402, login failure, account-related errors
4	Request body, model ID, parameters, tools, JSON Output	400 or 422 errors
5	Concurrency, retries, 429, long queues, keep-alives	Rate-limit errors, long waiting, empty lines, SSE keep-alive comments
6	Official status and upstream incidents	Many users affected, API or web chat incident reported

Layer 1 — Browser, app, and device

Start with the local client because it is the fastest layer to isolate. If DeepSeek works in a different browser or on a different device, the issue is probably local rather than a DeepSeek-wide outage.

Browser checks

• Open the official DeepSeek chat in a private or incognito window.
• Try another modern browser such as Chrome, Edge, Firefox, or Safari.
• Disable ad blockers, script blockers, privacy extensions, and aggressive content filters temporarily.
• Clear cookies and site data for DeepSeek domains if login or page loading fails repeatedly.
• Check whether JavaScript is enabled.
• Open your browser console only if you are comfortable debugging web errors; look for blocked scripts, CORS errors, network failures, or service-worker issues.

App checks

• Close and reopen the official DeepSeek app.
• Check the official app store or download page for updates.
• Restart the device if the app freezes, crashes, or fails to connect.
• On Android, clear app cache if the app repeatedly fails after login.
• On iOS, reinstalling the app can serve as a clean reset if cache clearing is not available.
• Check whether Data Saver, battery saver, or per-app network restrictions are blocking the app.

Device isolation rule

If DeepSeek works on your phone but not your laptop, focus on the laptop browser, extensions, DNS, firewall, or local network settings. If it fails on every device and every network, move toward status, account, or upstream checks.

Layer 2 — Network, DNS, proxy, and firewall

A healthy browser or app still cannot work if your network cannot reach DeepSeek. Test connectivity before changing application code.

• General connectivity: Confirm other sites load normally.
• Different network: Switch from Wi-Fi to mobile data, or try a mobile hotspot.
• DNS route: Test from a different network or DNS configuration if DeepSeek domains do not resolve.
• VPN/proxy: If you use a VPN, test with it on and off. Some networks block or degrade AI services.
• Corporate firewall: On work or school networks, confirm that deepseek.com, chat.deepseek.com, and api.deepseek.com are allowed.
• API reachability: If API requests time out before any HTTP status is returned, investigate DNS, proxy, firewall, or routing first.

For developers, a basic connectivity test can separate network problems from authentication problems. If the API returns a 401, your machine reached DeepSeek but the key was wrong or missing. If DNS fails or the connection times out, fix network reachability first.

Layer 3 — Login, API key, and balance

Authentication and billing issues are common when the DeepSeek API appears “down” but the service is actually reachable.

Web or app login issues

• Confirm you are using the official DeepSeek website or app for account login.
• Reset your password through official account recovery if login fails.
• Try a clean browser session if the login page loops or fails after authentication.
• Check whether your account is restricted, suspended, or waiting for verification.
• Do not enter official DeepSeek account credentials into unofficial pages.

API key issues

For API calls, the correct authorization format is:

Authorization: Bearer YOUR_DEEPSEEK_API_KEY

Common mistakes include using the wrong header, using an OpenAI key with DeepSeek, using a DeepSeek key against the default OpenAI endpoint, copying a key with extra spaces, or storing the key in the wrong environment variable.

Balance issues

If the API returns a 402 error, the issue is not model behavior or request format. It means the account has insufficient balance. Check billing and top up through the official DeepSeek platform.

Layer 4 — Request body, model ID, and V4 configuration

If authentication works but the API still fails, inspect the request itself. This is the layer where old V3.2-era examples can create confusion.

Use current model IDs in new API calls

For new API integrations, use the current V4 model IDs:

Current model ID	Use it for	Troubleshooting note
deepseek-v4-flash	Fast chat, low-cost usage, summaries, extraction, classification, routine coding help, lightweight tools	Best first model for simple debugging and minimal API tests.
deepseek-v4-pro	Hard reasoning, complex coding, long-context analysis, agentic workflows, tool planning	Use when the task needs stronger reasoning or higher quality.

The older names deepseek-chat and deepseek-reasoner are legacy compatibility aliases. They may still work during the transition period, but if a troubleshooting guide or code sample calls them the current primary models, that information is outdated.

Minimal current curl test

Use this small request to confirm that your key, base URL, model ID, and JSON body are valid:

curl https://api.deepseek.com/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer ${DEEPSEEK_API_KEY}" \
  -d '{
    "model": "deepseek-v4-flash",
    "messages": [
      {"role": "user", "content": "Reply with: DeepSeek API works."}
    ],
    "thinking": {"type": "disabled"},
    "stream": false
  }'

Minimal current Python test

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["DEEPSEEK_API_KEY"],
    base_url="https://api.deepseek.com",
)

response = client.chat.completions.create(
    model="deepseek-v4-flash",
    messages=[
        {"role": "user", "content": "Reply with: DeepSeek API works."}
    ],
    extra_body={"thinking": {"type": "disabled"}},
    stream=False,
)

print(response.choices[0].message.content)

Request-format checklist

• Use https://api.deepseek.com as the normal OpenAI-compatible base URL.
• Use /chat/completions or the OpenAI SDK chat-completions method.
• Include a valid model.
• Include a valid messages array.
• Do not send unsupported parameters.
• For JSON Output, use response_format={"type":"json_object"} and explicitly ask for JSON in the prompt.
• For Tool Calls, make sure the tool schema is valid and your application returns matching tool_call_id values.
• For strict tool schemas, use the beta base URL only where official docs require it.
• For thinking mode, keep reasoning_content separate from final content and preserve full assistant messages inside active tool-call loops.

Common DeepSeek API error codes

The HTTP status code usually tells you which layer to debug first.

Status	Meaning	Most likely cause	What to do
400	Invalid request body format	Malformed JSON, wrong message order, bad tool loop, invalid request body	Compare your request to the official Chat Completion schema and simplify to a minimal request.
401	Authentication fails	Wrong API key, missing key, wrong provider endpoint	Check DEEPSEEK_API_KEY and the Authorization: Bearer header.
402	Insufficient balance	Account balance has run out	Check balance and billing on the official DeepSeek platform.
422	Invalid parameters	Unsupported parameter, invalid model ID, bad schema, incompatible field	Remove unsupported fields and follow the API reference.
429	Rate limit reached	Requests sent too quickly or concurrency is too high	Reduce concurrency, queue work, and use backoff.
500	Server error	Temporary provider-side issue	Retry after a brief wait and log the request details.
503	Server overloaded	High traffic or temporary overload	Retry later, use graceful fallback, and check status pages.

In general, 400, 401, 402, and 422 are usually issues you can fix in your request, key, account, or parameters. 500 and 503 usually point to temporary upstream issues. 429 means you need pacing and retry control.

Layer 5 — Rate limits, concurrency, timeouts, and keep-alives

DeepSeek API concurrency is dynamic and can depend on server load. A 429 response means your requests are being sent too quickly or your concurrency is too high.

How to handle 429

• Reduce request concurrency.
• Use a queue instead of firing many requests at once.
• Add exponential backoff with jitter.
• Set a retry budget instead of retrying indefinitely.
• Log 429 responses by feature, model, user, and route.
• Do not let error-handling code immediately retry in a tight loop.

Empty lines and SSE keep-alive comments

During busy periods, non-streaming API requests may remain connected and return empty lines while waiting. Streaming requests may return SSE keep-alive comments such as : keep-alive. If you parse raw HTTP responses yourself, ignore those keep-alive signals and wait for the real response body or final stream event.

Timeouts

If a request has not started inference after a long waiting period, the server may close the connection. Your application should set timeouts, handle closed connections cleanly, and provide user-facing fallback messages instead of hanging forever.

Layer 6 — Official status and upstream incidents

After local, network, account, and request checks are ruled out, check upstream status. Use the official status page to see whether API service or web chat service has an active incident, degraded performance, partial outage, major outage, or maintenance.

• Check the official DeepSeek status page.
• Compare API and Web Chat components separately.
• Check recent incidents if the problem began around a specific time.
• Do not keep changing code if the official status page confirms an active incident.
• If you run a production application, show a graceful message and retry later instead of retrying aggressively.

For an independent navigation page with official links, use our DeepSeek status guide.

Web and app-specific troubleshooting

DeepSeek web chat problems

• Try the official web chat in another browser.
• Disable browser extensions temporarily.
• Clear DeepSeek cookies and site storage.
• Check if the login page works in a private window.
• Make sure your browser allows scripts and cookies required by the app.
• Try a shorter prompt if long outputs or large files trigger timeouts.
• Check official status if both login and chat fail.

DeepSeek app problems

• Update the official DeepSeek app.
• Restart the app and device.
• Check whether the app works on Wi-Fi and mobile data.
• Clear app cache where available.
• Reinstall the app if crashes continue.
• Check app permissions for network, files, microphone, or other features you use.
• Use the official web chat as a temporary comparison point.

API vs web/app behavior

The official web/app experience and the developer API are not always identical. API behavior depends on API model IDs, parameters, billing, tokens, rate behavior, and the request format. Do not assume that a web feature maps one-to-one to a single API parameter.

Minimal API debug checklist

1. Check official DeepSeek status first.
2. Confirm your machine can reach api.deepseek.com.
3. Confirm your API key is loaded in the environment.
4. Confirm you are using Authorization: Bearer YOUR_API_KEY.
5. Use https://api.deepseek.com as the base URL.
6. Use deepseek-v4-flash for the first minimal test.
7. Send one simple non-streaming request with thinking disabled.
8. If that works, add streaming, JSON Output, Tool Calls, or thinking mode one feature at a time.
9. Log HTTP status, model ID, request body shape, finish reason, and usage fields.
10. Do not debug a complex agent or RAG workflow before a minimal request works.

Current V4 model troubleshooting

Choose the simplest model and mode that can validate the failing route. This prevents you from confusing model selection with authentication, request format, or networking issues.

Problem	Best first test	Why
API does not respond at all	Connectivity and status check	Model choice is irrelevant if the request never reaches DeepSeek.
401 error	API key and Bearer header	Authentication must work before model debugging.
402 error	Balance check	Billing must be resolved before requests can succeed.
400 or 422 error	deepseek-v4-flash minimal request	Start with the simplest valid model call and add complexity later.
Slow simple chat	deepseek-v4-flash non-thinking mode	Flash is the better first latency/cost test.
Reasoning quality issue	deepseek-v4-pro with thinking enabled	Pro is the better test for harder reasoning tasks.
Tool-loop failure	Minimal one-tool call with deepseek-v4-flash	Debug tool schema and message order before using complex agents.
JSON Output failure	Minimal JSON request with explicit JSON instruction	Validate prompt, response_format, and output length.

Legacy aliases and migration problems

The names deepseek-chat and deepseek-reasoner are now legacy compatibility aliases. If old code still uses them, that can be a migration risk even if requests still work today.

Legacy alias	Current compatibility behavior	Recommended replacement
deepseek-chat	Routes to deepseek-v4-flash non-thinking mode	deepseek-v4-flash with thinking disabled
deepseek-reasoner	Routes to deepseek-v4-flash thinking mode	deepseek-v4-flash or deepseek-v4-pro with thinking enabled

Migration fix: replace old examples that use deepseek-chat with deepseek-v4-flash. Replace reasoning-heavy examples that use deepseek-reasoner with deepseek-v4-pro plus thinking enabled when quality matters more than lowest cost.

Production troubleshooting checklist

• Keep a minimal known-good API request in your monitoring suite.
• Track API status, latency, response status, model ID, route, user-facing feature, and request size.
• Log request IDs or provider metadata where available.
• Log token usage fields when requests complete.
• Use separate dashboards for web chat issues, app issues, API issues, and account/billing issues.
• Use retry budgets, not infinite retries.
• Use queues for high-volume workloads.
• Validate JSON Output before using it.
• Validate Tool Call arguments before executing tools.
• Do not expose API keys in browser or mobile app code.
• Re-check official model names and pricing before release notes, public docs, or customer-facing calculators.

Related DeepSeek guides

• DeepSeek Status Guide — status checks and outage links
• DeepSeek API Guide — current V4 model IDs, base URL, API setup, and migration notes
• DeepSeek API Error Codes — error-by-error debugging
• DeepSeek Token Usage — usage object, streaming usage, and cost calculation
• DeepSeek Thinking Mode — thinking and non-thinking behavior
• DeepSeek Tool Calls — function calling and tool-loop debugging
• DeepSeek JSON Output — structured JSON response troubleshooting
• DeepSeek API Pricing — current V4 rates and billing explanation
• DeepSeek App Guide — official app usage and mobile notes
• DeepSeek Login Guide — account access and login navigation

FAQ

Conclusion

When DeepSeek is not working, the fastest path is a layered diagnosis. Start with status, then check browser or app behavior, network reachability, login, API key, account balance, request body, model ID, rate limits, and upstream incidents. For new API troubleshooting, use deepseek-v4-flash or deepseek-v4-pro, not old V3.2-era wording.

Most issues are solved before reaching the upstream-status layer. If a minimal V4 API request works, add complexity back one step at a time: streaming, JSON Output, Tool Calls, thinking mode, long context, RAG, agents, and production retries. This prevents one broken feature from making the whole service look unavailable.

Official sources and last verified

Last verified: April 24, 2026. DeepSeek model names, pricing, endpoint behavior, error codes, status, rate behavior, and app behavior can change. Use the official sources below when making production decisions.

• DeepSeek official website
• Official DeepSeek Chat
• DeepSeek app page
• DeepSeek official status page
• DeepSeek API quick start
• DeepSeek-V4 Preview Release
• DeepSeek Models & Pricing
• DeepSeek Create Chat Completion API Reference
• DeepSeek Error Codes
• DeepSeek Rate Limit
• DeepSeek Thinking Mode
• DeepSeek JSON Output
• DeepSeek Tool Calls
• DeepSeek Context Caching