Restarting a build does not work since some days

When I try to restart a build, I only get this stupid error message:
“Oh no! An error occurred. The job could not be restarted.”

This problem is 100% reproducible. Since at least ca. 2 weeks, I am unable to restart any build in any of my repositories.

Wishlist: Error messages should be somewhat informative, giving an explanation what went wrong. This kind of non-informative error messages in Travis CI is really annoying.

Duplicate of