Blacklisted IP?

Is it possible that my client got blacklisted IP because of wrong password?
She left the same account with host in Outlook and added another account with IMAP settings.
The box with login kept popping out for first account and then all communication stopped from her home router. It works on other locations and she tried pinging the mail sub-domain from home, but got no pong.

Quite likely. I’ll tune this up a bit but there is an amount of login failures that will result in temporary IP block. I’ve cleared the list.