Gitlab CI doesn't close the milestone

[Topin2001]

Describe the bug

When a milestone is complete and supposed to be close, this CI doesn't work

To reproduce

Merge on master branch a PR that will complete a milestone

Expected behavior

The milestone is supposed to be closed

Screenshots & log

{
 "message": "Bad credentials",
 "documentation_url": "https://docs.github.com/rest"
}