How to block a user from entering the mail?

Question

Email

The problem is this. there is one user who uses his own personal mail place, is it possible to somehow block the entrance to a certain mail on a PC?

Answer 1

Or sniff his login and password from his mail and just send out a mailing list to his contacts

And get a claim on a whole wide range - from personal data to the protection of honor and dignity. No one bothers to sniff the login-password. You can even enter the mail and make sure that he did not distribute anything and did not send himself anything "extra", although this is already a "near-legal" event. But you don’t need to write on his behalf - a litigator will come across, he will turn the office inside out ...

Answer 2

Redirect domain in hosts to 127.0.0.1 from simple.

Answer 3

Can parental controls help you?
And you can write more about the mail. Does it
come from the application? Browser? Flash drives?