Getting any of the above error messages in the course of performing an action can be a bit infuriating.
These error messages are temporary and occur at times as a result of a technical or network glitch. What you need to do is to wait for a while and then follow the steps below to have it fixed:
1. If you're logged in, log out of your account
2. Clear your browser's history/browsing data/cached data
3. Reload your page
4. Log in and then try performing that action all over again
If the error persists after performing the above action, kindly contact support at email@example.com with details of what you're trying to do for further assistance.