Mail notification horror!

I’ve remembered that did not allow smtp on firewall for rocketchat and made a mistake to turn it on.
All notification settings for snap 3.2.2 were in default.

My users began to recieve tons of idle messages. I’ve turned offline notifications off but it did not help.
So I’ve turned all notifications off. And set smtp server field to empty.

When I pressed LDAP sync. All my deactivated users became activated. It is the very old bug. And the whole company received strange messages about “account was activated”.
Smtp server field is empty. And I have to reply everyone now what it was. Just “account is activated”.

Mail notifications in Rocketchat are some sort of disaster that should be blocked by firewall.