It sounds like a frustrating situation, there could be a few reasons why your collaborators are experiencing this issue. Try to Role Changes like Double-check that their roles haven't inadvertently changed. Sometimes, permissions can get altered without anyone realizing it. Also Repository Settings try to make sure the repository settings haven't been updated to restrict push access. Also SSH Keys If they're using SSH keys, confirm that their keys are still valid and haven't been revoked or changed. This can sometimes cause permission issues and Branch Protection Rules Check if there are any branch protection rules in place that might be preventing pushes to the branch