### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet - [x] This is a single bug report (please file separate reports for different bugs) - [x] I am using the latest version of Claude Code ### What's Wrong? Whenever I try to re-authenticate the teamwork MCP it gives me below error - """SDK auth failed: redirect URI host "localhost:55385" is no longer supporte

[BUG] SDK auth failed: redirect URI host "localhost:55385" is no longer supported (sunset 2026-08-01)

Status Fixed / completed

Reported on v2.1.228

Maintainer reply ✓ Yes — bcherny

Activity 3 comments · opened Aug 12, 2026 · closed Aug 19, 2026

💡 Likely answer: A maintainer (bcherny, collaborator) responded on this thread — see the highlighted reply below.

Preflight Checklist

[x] I have searched existing issues and this hasn't been reported yet
[x] This is a single bug report (please file separate reports for different bugs)
[x] I am using the latest version of Claude Code

What's Wrong?

Whenever I try to re-authenticate the teamwork MCP it gives me below error -
"""SDK auth failed: redirect URI host "localhost:55385" is no longer supported (sunset 2026-08-01)"""

I have tried multiple suggestions claude made and raising this issue here is the final one.
As per claude the localhost should here be automatically replaced by 127.0.0.0 but that does not happen and I keep getting this error. This has slowed me down from working with teamwork fetching reports, analysing them, or even making calls to get teamwork entries, add/update entries.

Please help.

What Should Happen?

Whenever I try to re-authenticate any MCP it should not run into this """SDK auth failed: redirect URI host "localhost:55385" is no longer supported (sunset 2026-08-01)""" error. Instead the browser should open and I should be able to authenticate and work again using the MCP.

Error Messages/Logs

SDK auth failed: redirect URI host "localhost:55385" is no longer supported (sunset 2026-08-01)

Steps to Reproduce

/mcp

Navigate to teamwork mcp and hit return/enter

select Authenticate/Re-authenticate

Boom, the error is there.
SDK auth failed: redirect URI host "localhost:55385" is no longer supported (sunset 2026-08-01)

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Not sure but it worked below 2.1.228 maybe. Maybe even before that, don't remember the last version it worked.

Claude Code Version

2.1.228 (Claude Code)

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Not that I can think of

View original on GitHub ↗

3 Comments

cbragado-eurocastalia · 1 month ago

Confirming this is still broken on 2.1.233 (claude update shows it as latest). Same teamwork MCP server (https://mcp.ai.teamwork.com/, protocol 2026-07-28).

Sequence:

/mcp showed teamwork as ✔ Connected, but none of its ~195 tool schemas were exposed to the session (had to be worked around).
Re-running /mcp on teamwork showed Status: ✔ connected, Auth: ✔ authenticated, but SDK auth failed: Dynamic Client Registration rejected (HTTP 400): {"error":"invalid_redirect_uri","error_description":"redirect URI host \"localhost:3118\" is no longer supported (sunset 2026-08-01)"}.
Tried "Reconnect" and "Re-authenticate" from the /mcp menu — same error, different random port each time (next attempt: localhost:62030). Host is always rejected regardless of port, confirming it's not a one-off port collision.

Platform: macOS, Claude Code 2.1.233. Blocks all twprojects-*/twdesk-*/twspaces-* calls — same practical impact as reported above (can't create/update projects, tasks, etc. via MCP).

bcherny collaborator · 1 month ago

Fixed in 2.1.229 — changelog: "Fixed MCP OAuth with strict authorization servers by using 127.0.0.1 instead of localhost in the redirect URI" (https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md). Closing — reply to reopen if it still happens on the latest version.

🤖 Generated with Claude Code

github-actions[bot] · 4 days ago

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.