Hey Albert,
thanks for your competent reply.
Yes, Xcode release candidate 26.5 (17F42).
I have deleted the cache. I have also deleted codex* and chatgpt* (empty) from the system keychain. No VPN connection. The problem persists.
I have now switched Xcode over to use "Authenticate with configuration file". It does that, but I am unsure whether the configuration file works, and I don't really know how to check. The codex* entries in keychain are back since I logged in on the Codex app.
Kind regards