GitHub Git github.com: Permission denied error with existing deploy keys

Am I only the one getting this error on existing deploy keys on GitHub:

git@github.com: Permission denied (publickey). fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.

A deploy key that used to work does not anymore.

It has been happening for the last 2 hours. And this happens to several of my deploy keys, like 4 already affected.