Github Copilot CLI: Model call failed: "Connection error."

[ajayrathiif]

Describe the bug

I’m trying to use GitHub Copilot but am encountering the issue shown in the screenshot. My company has an active GitHub subscription with the Copilot CLI feature enabled. However, I noticed that no list of available models appears, I had to manually connect to gpt-5, after which I received the error:
“Execution failed: Connection error.”

I’ve already tried restarting the terminal and VS Code, reauthorizing the GitHub connection, and even testing it on a colleague’s system . the issue persists. Could it be that my company’s network proxy is blocking connections to the Copilot CLI API?

Any insights or suggestions would be greatly appreciated.

Affected version

0.0.337

Steps to reproduce the behavior

No response

Expected behavior

No response

Additional context

No response

[non-stop-dev]

Yup, I have errors to call the model too. In my case the error is:

[damianh]

I too started to get the errors above after I updated the cli. I've downgraded to 0.0.328 and things seem to work again.

[non-stop-dev]

I upgraded yesterday and have been working until today nicely. Error appeared in the middle of the session. However if I start a new session, there is no problem with Model Call... seems like it only affects ongoing chats.

I got similar issues in the past when trying to continue a Truncated chat.

[mikewaters]

Same. Downgrade to 0.0.330 has addressed for me.

Enterprise customer, copilot business subscription, yadda yadda.

[mikewaters]

Hm, this may be a dupe of #116

[ajayrathiif]

Same. Downgrade to 0.0.330 has addressed for me.

Enterprise customer, copilot business subscription, yadda yadda.

I will try to downgrade the version and see if works.

[ajayrathi2004]

it worked for me after downgrading: below are the steps
Steps to downgrade GitHub Copilot CLI:

My current version is/mode: 0.0.338
Remove the existing installation: npm uninstall -g @github/copilot
Install the previous version: npm install -g @github/copilot@0.0.330
Switch to the Claude model: /model claude-sonnet-4
Test with a simple query: "Who are you"
Copilot responded

[rcastro-ni]

Same bug. I get these errors on versions 0.0.338 down to 0.0.336
✗ Model call failed: "Connection error."
✗ Execution failed: Connection error.

And these erros on versions 0.0.335 and 0.0.334
✗ Model call failed: "421 421 Misdirected Request\n"
✗ Execution failed: 421 421 Misdirected Request

Version 0.0.330 works.

[alperenoezkan]

it worked for me after downgrading: below are the steps Steps to downgrade GitHub Copilot CLI:

My current version is/mode: 0.0.338 Remove the existing installation: npm uninstall -g @github/copilot Install the previous version: npm install -g @github/copilot@0.0.330 Switch to the Claude model: /model claude-sonnet-4 Test with a simple query: "Who are you" Copilot responded

I applied these steps and worked. Also my colleague had the same issue after upgrading to the latest version of copilot cli today.