GitHub Copilot Chat: Error "Language model unavailable" during service degradation

[puncakbergaya]

Description:
I am unable to use GitHub Copilot Chat. Every time I try to send a message, I receive the error message: "Language model unavailable".

Steps to Reproduce:

1. Open Visual Studio Code.
2. Open GitHub Copilot Chat panel.
3. Type any query and press Enter.
4. The error "Language model unavailable" appears.

Additional Context:

1. I have tried signing out and signing back in to GitHub.
2. I have restarted VS Code multiple times.
3. I am aware that GitHub Status is currently "Yellow" with reported degradation in Copilot services (as of April 14, 2026).

However, the chat remains unusable even after these attempts.

[shivioua]

Duplicate? #309766