Getting error 401 if deleting many credentials quickly

Description of problem

When deletion of credentials is massive and quick - after some while `Error 401` is shown in balloon message in top-right corner and credential is not getting deleted. Faced this when using UI automation which means deletion is really quick.

How reproducible

Intermittent

Steps to Reproduce:

1. Create at lease 25 credentials of any type
2. Remove them quickly

Actual results

After some while `Error 401` is shown in balloon message in top-right corner and credential is not getting deleted

Expected results

All is deleted, no errors

Additional info