[BUG] API Error 401 - OAuth error

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Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/33217
2. https://github.com/anthropics/claude-code/issues/33214
3. https://github.com/anthropics/claude-code/issues/33213

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🤖 Generated with Claude Code

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try /logout and then /login again. it worked for me

Root Cause

Claude Code v2.1.72 appears to fail during the OAuth authentication flow. The CLI attempts to exchange the OAuth authorization code for an access token, but the request times out:

OAuth error: timeout of 15000ms exceeded

After the timeout occurs, Claude Code proceeds without a valid token, which causes the subsequent API request to fail with:

API Error: 401
Invalid authentication credentials

This indicates the OAuth token exchange step is failing or timing out, leaving the CLI in an unauthenticated state.

---

Proposed Fix

Improve the OAuth token exchange logic by:

1. Increasing the timeout window for the token exchange request.
2. Adding retry logic if the exchange request times out.
3. Preventing API calls until authentication completes successfully.

---

Example Patch (TypeScript)

Increase OAuth Timeout

const OAUTH_TIMEOUT_MS = 60000; // increase from 15000ms

const response = await axios.post(
  tokenEndpoint,
  payload,
  { timeout: OAUTH_TIMEOUT_MS }
);
Add Retry Logic for Token Exchange
async function exchangeOAuthToken(code: string) {
  const MAX_RETRIES = 2;

  for (let attempt = 0; attempt <= MAX_RETRIES; attempt++) {
    try {
      return await requestToken(code);
    } catch (err: any) {
      if (attempt === MAX_RETRIES) throw err;

      if (err.message?.includes("timeout")) {
        await new Promise(r => setTimeout(r, 1000));
      } else {
        throw err;
      }
    }
  }
}
Prevent API Calls Without Valid Token
if (!authToken) {
  throw new Error("Authentication failed. Please run /login again.");
}
Expected Result After Fix

/login completes without timing out.

OAuth token exchange succeeds.

Claude Code stores the access token locally.

API requests no longer return 401 Invalid authentication credentials.

Impact

Fixes login failures introduced in Claude Code v2.1.72.

Prevents authentication from failing due to short network timeouts.

Improves reliability for slower networks or delayed OAuth responses.

I found a workaround for this issue. I used the binary from a previous version (2.1.50), which can be found in ~/.local/share/claude/versions. I logged in using that version, and once the authentication was successful, I was able to switch back and use the latest version (2.1.72) without any problems."

this is happening again, 6:51 pm PST :(

It is happening again:
API Error: 500 {"type":"error","error":{"type":"api_error","message":"Internal
server error"},"request_id":

Why do we as customers have to go through this over and over again? This is simply a resource allocation matter. We are paying for the service already!

@claude ^

this is back again:
Please run /login · API Error: 401
{"type":"error","error":{"type":"authentication_error","message":"OAuth token has
expired. Please obtain a new token or refresh your existing
token."},"request_id":"req_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"}

OAuth error: timeout of 15000ms exceeded

We are losing critical work hours for a paid service?!?

@claude ^

From interaction with Fin (Claude Support) the following helped me:

This 401 is most likely Claude Code picking up an API key (or an old/expired credential) instead of using your Pro OAuth token.

Try this exact sequence:
Run /logout (even if it returns 401).
Run claude update.
Fully restart your terminal (quit the terminal app, reopen).
Run claude and complete the login again.

Also double-check you have no ANTHROPIC_API_KEY anywhere in your shell profile (.zshrc/.bashrc/.profile) and run unset ANTHROPIC_API_KEY before starting Claude Code, since an API key takes precedence and can cause 401s if it’s disabled/expired.

I hope this helps others!

Thanks @BrianSlatts1980. did not work.
here we go again, Monday morning and this is back again:
API Error: 500 {"type":"error","error":{"type":"api_error","message":"Internal
server error"},"request_id":"req_00000000000000000000000"}

Closing for now — inactive for too long. Please open a new issue if this is still relevant.