Hey,
all of our cloud builds are also failing since August 3rd. Even inactive repos which we havent touched in a few weeks.
Were also using the Plastic Cloud. I have tried re authenticating the repo to UCB with a plastic account and the Unity ID verification (even with the new long live api token) but its still broken for us.
I also havent heard from Unity support for a week. They asked to replay the last successful build but that also failed.