[Bug]: dstack server returns 500 for endpoints if backend credentials became invalid #555
Description
dstack version
master
Python version
3.11
Host OS
macOS 13.4
Host Arch
ARM
What happened?
If the credentials used to create a project became invalid, or if the set up default credentials are no longer available, the server returns 500 errors. Also, the logs are full of errors printed by background workers. The server should return appropriate error codes/emit warnings. The frontend should display error notification.
Relevant log output
No response
Additional Information
No response