Claude Code Errors: The Essential Fix List for 400, 403, 429 and 529

Claude Code errors tend to show up at the worst moment, and the message is usually half a sentence. This page is my lookup table. Every entry was checked on October 21, 2026 against Anthropic’s error reference and install troubleshooting page; when something isn’t in the official docs, I say so instead of guessing.

Each of these Claude Code errors has a number. I = install, A = login (auth), U = usage. Install problems live on the install guide; login and usage problems are below. Find your message in the table, click the number, done.

Claude Code errors lookup table

Message you see	Jump to	Stage
command not found: claude	I1	install
EACCES: permission denied	I3	install
npm WARN EBADENGINE	I4	install
curl: (22) ... 403 / App unavailable in region	I8	install
OAuth error: Invalid code	A1	login
API Error: 403 Request not allowed	A2	login
OAuth error: Request failed with status code 403	A2	login
Your organization has disabled Claude subscription access	A2	login
Paste code here if prompted (stuck)	A3	login
Not logged in · Please run /login	A4	login
Repeated 529 Overloaded errors	U1	usage
Request rejected (429)	U2	usage
You've hit your session limit	U3	usage
You've hit your weekly limit	U3	usage
Usage credits required for 1M context	U4	usage
This organization has been disabled	U5	usage
Credit balance is too low / Invalid API key	U6	usage
thinking.type.enabled is not supported	U7	usage
thinking type should be enabled or disabled	U7	usage
Error editing file / Error writing file	U8	usage
Error loading webview	U9	usage
Claude Code error today (is it down?)	U10	usage
Your account is on hold	U11	usage

Check this first: which credential is Claude Code using?

Honestly, a third of the Claude Code errors I’ve helped people with came down to one thing. Claude Code uses the first credential it finds, in this order: cloud provider settings, ANTHROPIC_AUTH_TOKEN, ANTHROPIC_API_KEY, an apiKeyHelper script, CLAUDE_CODE_OAUTH_TOKEN, then your /login subscription (official order). So an old API key in ~/.zshrc or a project’s .env quietly wins over the Pro plan you’re paying for. In -p mode the key is always used.

Run /status. If there’s an API key row you didn’t expect, that’s likely your 400, your 401, your 429 or your “credit balance” message. Fixing it takes ten seconds and clears a surprising number of Claude Code errors at once.

Login errors A1 to A4

A1. Login fails: the general reset

The official reset is boring and works: /logout, quit Claude Code, run claude again and log in. OAuth error: Invalid code. Please make sure the full code was copied means the code expired or got cut off, so finish quickly after the browser opens. Failed to start OAuth callback server means Claude Code can’t listen on 127.0.0.1 (common in sandboxes); the docs suggest running claude setup-token on a machine where login works and setting the result as CLAUDE_CODE_OAUTH_TOKEN (source).

A2. API Error: 403 Request not allowed / OAuth 403

The official checklist for a 403 after login: on Pro or Max, open claude.ai/settings and confirm the subscription is actually active (remember Free doesn’t include Claude Code). On a Console account, you need the “Claude Code” or “Developer” role, which an admin assigns (source).

A cousin of this one: Your organization has disabled Claude subscription access for Claude Code. That’s a server-side org setting. Nothing local overrides it; ask your admin, or use a Console API key (source).

A3. Login stuck in WSL2, SSH or a container

The browser opens somewhere the callback can’t reach. The browser page shows a code; paste it at Paste code here if prompted. If pasting doesn’t work, use claude auth login. In WSL2, if no browser opens at all, set BROWSER to your Windows browser path and retry (source).

A4. Not logged in · Please run /login (again and again)

Run /login. If it keeps happening, check that your system clock is right. On macOS a locked Keychain is a known cause; claude doctor will flag macOS Keychain is not writable. There was also a bug before v2.1.211 where waking from sleep logged all sessions out at once, so update if you’re behind (source).

Usage errors U1 to U11

U1. 529 Overloaded (and 500)

API Error: Repeated 529 Overloaded errors means the API is at capacity. It’s not your quota, and Anthropic says it doesn’t count against your limits. Claude Code already retried before showing it. Wait a few minutes, check status.claude.com, or switch model with /model, since capacity is tracked per model. A 500 Internal server error is also on their side (source).

U2. 429 Request rejected

Official meaning: you hit the rate limit of an API key, a Bedrock project or a Google Cloud project. That’s the pay-per-token path, not your subscription. So run /status first; a stray ANTHROPIC_API_KEY can route you through a low-tier key. Otherwise lower concurrency or ask for a higher tier. The different-looking Server is temporarily limiting requests (not your usage limit) is a short server throttle, and since v2.1.199 Claude Code retries it automatically (source).

U3. You’ve hit your session limit / weekly limit

This is your plan quota. The messages look like You've hit your session limit · resets 3:45pm or You've hit your weekly limit · resets Mon 12:00am. Session and weekly limits are shared across models, so switching model won’t help; the separate Opus or Sonnet limits are the exception. Run /usage to see when you reset, /usage-credits to buy extra usage on Pro or Max, and since v2.1.234 Claude Code can wait and continue automatically after the reset (the setting is in /config) (source). How the two clocks interact is in Claude usage limits explained.

If you searched “claude code usage limit bug”: there’s a big open GitHub thread, issue #16157, where Max users report limits draining unusually fast. It had 1,499 comments when I checked. Anthropic hasn’t posted an official explanation that I could find, so I’m not going to pretend to know the cause.

U4. Usage credits required for 1M context

Not a quota problem. You picked a [1m] model and your plan only includes 1M context through usage credits. /model and pick the variant without [1m], or turn on usage credits and restart. CLAUDE_CODE_DISABLE_1M_CONTEXT=1 hides those variants entirely (source).

U5. 400 This organization has been disabled

Scary wording, usually harmless. Per the docs, Claude Code is using a stale ANTHROPIC_API_KEY from a disabled Console organization, often an old job’s key in your shell profile. It is not your subscription being banned. Run unset ANTHROPIC_API_KEY (PowerShell: Remove-Item Env:ANTHROPIC_API_KEY), delete it from your profile, relaunch, check /status. No variable set and it still happens? Contact support (source). I go through the difference between this and a real account suspension in my Claude account ban notes.

U6. Credit balance is too low / Invalid API key / 401

Credit balance is too low: your Console org ran out of prepaid credit, or (again) an API key is overriding your subscription. Invalid API key: typo, revoked key, or invisible characters; env | grep ANTHROPIC finds keys loaded by direnv or .env. 401 Invalid authentication credentials: check /status, then /login once (source).

U7. 400 errors about thinking

"thinking.type.enabled" is not supported for this model means your Claude Code is older than the model needs. claude update and restart. Official minimums: Opus 4.7 needs v2.1.111, Opus 4.8 v2.1.154, Sonnet 5 v2.1.197, Opus 5 v2.1.219, Opus 5.5 v2.1.280, Sonnet 5.5 v2.1.284. On the stable channel you may need to switch to latest (source).

API Error: 400 thinking type should be enabled or disabled is a different animal. That text is not in Anthropic’s error reference at all. As far as I can tell it comes from a non-Anthropic endpoint, when ANTHROPIC_BASE_URL points at a third-party “compatible” API that doesn’t accept Claude Code’s thinking settings. Run echo $ANTHROPIC_BASE_URL. With Anthropic’s own API or a subscription you shouldn’t see it. I don’t troubleshoot third-party endpoints here.

400 due to tool use concurrency issues means the conversation history got corrupted; /rewind as the message suggests (source).

U8. Error editing file / Error writing file

The chat view only shows the short Error editing file; the real reason is in the transcript view (Ctrl+O), and Claude usually retries on its own. A common one is Found 2 matches of the string to replace, meaning the text wasn’t unique (#3337). “Error writing file” has no entry in the official reference, so I can’t tell you an official meaning; check the transcript for the underlying message.

U9. VS Code: Error loading webview

No official entry for this either. What the docs do say: the extension needs VS Code 1.94.0 or newer. The usual report looks like #24142 (a service worker failing to register, now closed). Update VS Code and the extension first, then reload the window. Beyond that it’s community guesswork, and I’d rather not pass it off as a fix.

U10. Is Claude Code down today?

Check status.claude.com (the old status.anthropic.com redirects there). When I looked on October 21 it said All Systems Operational; the most recent major incident listed was on October 7. If the status page is green and only you are seeing Claude Code errors, go back to /status.

U11. Your account is on hold

Your account is on hold and can't use Claude Code. View details or appeal: https://claude.ai/restricted. Logging in again won’t fix it, because the hold is on the account. The only route I’ll point you to is the official one: open that link, read the details, appeal through Anthropic’s safeguards and appeals page. Refunds after a suspension: I couldn’t find an official policy specific to that, only the general refund terms. More in what to do when your Claude account is banned.

Install errors live on the install page

Claude Code errors that happen before your first login (PATH, permissions, Node warnings, WSL, the wrong Windows shell, a 403 from the install script) are in the Claude Code install guide, numbered I1 to I9. Jump straight to I1 command not found or I8 install script 403.

Claude Code errors FAQ

What does Claude Code error 400 mean? Depends on the text after it. “organization has been disabled” is a stale API key (U5), “thinking.type.enabled” is an old version (U7), “thinking type should be enabled or disabled” is a third-party endpoint (U7).

Claude Code error 403? At login, an inactive plan or missing role (A2). At install, the script URL returned a page (I8).

Claude Code error 429 vs 529? 429 is an API key or cloud project rate limit (U2). 529 is Anthropic’s capacity, not your quota (U1).

Claude Code usage limit reached, when does it reset? The error message tells you, and /usage shows both windows. Changes to the limits are logged in my usage limit tracker.

Can I bring my Codex setup into Claude Code? Yes, officially with /import codex (commands reference), and --dry-run previews it. People also mention claude mcp serve; I couldn’t find it in Anthropic’s current docs, so don’t treat it as officially supported.

More on this: Claude Code install guide · Claude and Codex usage limit tracker · AI subscription and API price comparison · Claude category