[BUG] Claude CoWork showing Content Security Policy error after Mac OS update
Status Fixed / completed
Maintainer reply None cached
Activity 5 comments · opened Mar 12, 2026 · closed Mar 18, 2026
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?
Claude CoWork stopped being able to access the API. This used to work, but seems to have stopped after I updated my macOS to Tahoe 26.3.1
I get ECONNRESET.
Regular Claude chat works fine. This seems related to the VM.
I don't have any firewalls or VPNs.
What Should Happen?
CoWork should be able to connect to the API.
Error Messages/Logs
2026-03-12 16:06:57 [error] Uncaught Error: Minified React error #418; visit https://react.dev/errors/418?args[]=text&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
2026-03-12 16:07:29 [error] Connecting to 'https://a-api.anthropic.com/v1/m' violates the following Content Security Policy directive: "connect-src 'self' https://api.segment.io https://*.segment.io https://*.segment.com https://a-cdn.anthropic.com https://*.google.com https://*.facebook.com https://*.facebook.net https://*.doubleclick.net". The action has been blocked.
2026-03-12 16:07:29 [error] Fetch API cannot load https://a-api.anthropic.com/v1/m. Refused to connect because it violates the document's Content Security Policy.
2026-03-12 16:07:29 [error] Error sending segment performance metrics TypeError: Failed to fetchSteps to Reproduce
Open Claude Code and switch to CoWork tab.
Claude Model
Not sure / Multiple models
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
1.1.6452 5afc23
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
According to @MarshallOfSound is a red herring, per bug https://github.com/anthropics/claude-code/issues/18006
5 Comments
https://github.com/anthropics/claude-code/issues/18854 also seems related.
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
The suggested dupes seemed specific to Windows or made reference to recent patches to Claude.
It seems plausible that this might be a new incompatibility related to those issues, but triggered by the new MacOS.
Well. Duh.
Turns out this happened because the Mac Mini was connected to the internet via its wifi, but also had its ethernet port connected to the internet, but not authenticated.
Claude's VM apparently defaulted to the ethernet and then when it failed, didn't check any other interfaces? At least that's what I assume happened. Because once I unplugged the ethernet cable, Claude CoWork snapped back to life, with a helpful "Are you having API troubles? Tell me what's going on and I'll get things sorted."
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.