Anthropic API Authentication Error: OAuth Not Supported. (API ERROR 401)

Bug Description
Im receiving this error in all Claude Code Sessions, I tried downgrading but it persists (I also have a Max Plan) :

API Error: 401 {"type":"error","error":{"type":"authentication_error","message":"OAuth authentication is currently not
supported."},"request_id":"req_011CSHa1FurUZv2Lu8mxQdXf"}

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 1.0.83
• Feedback ID: 1433c0af-44fb-4a46-8ef0-92f9d3ce2580

Errors

[{"error":"Error: 401 {\"type\":\"error\",\"error\":{\"type\":\"authentication_error\",\"message\":\"OAuth authentication is currently not supported.\"},\"request_id\":\"req_011CSHa1FurUZv2Lu8mxQdXf\"}\n    at new tW (unknown:1:28)\n    at new wY (/$bunfs/root/claude:794:1964)\n    at new RW0 (unknown:1:28)\n    at generate (/$bunfs/root/claude:794:2456)\n    at makeRequest (/$bunfs/root/claude:811:5330)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-08-19T18:49:45.007Z"}]