We are trying to use a Secret Variable - PSCredential and the password generator randomly selected a sequence that might be problematic. Namely '$_ appears in the password.
Unfortunately, we are unable to run scripts using that credential. We get 500 error when trying to start a terminal session. And scripts can’t run for this credential.
You can download the logs from Settings \ General \ Diagnostics. It will download a zip file that contians a bunch of text files and there should be a log message in there with the prefix [ERR]