Bug: Exception on accessing not running database

[StraykerPL]

Describe the bug

When a user is trying to use app, eg. logging in, when the DBMS in turned off, exception is triggered.

To Reproduce

Steps to reproduce the behavior:

1. Go to Web Frontend via web browser,
2. Make sure DBMS is turned off,
3. Try to login,
4. See error in browser's console,

Expected behavior

Make Web Backend handle not working DBMS gracefully.

Screenshots

Desktop (please complete the following information):

Smartphone (please complete the following information):

Additional context