Can you verify that the person who made the commit is a current member of your Vercel team?
If the commit email address doesn’t match up with the one from your GitHub and Vercel accounts, then the deployment could be blocking it as an unrecognized user.
You can check the local setting by running the git config --global user.email. And you can update it with git config --global user.email "YOUR_EMAIL" if the email doesn’t match your account.