Our company has not been able to send out emails for 4 days now. Although the people I have been dealing with have been helpful they can't seem to remove the block.
Apparently we sent out an email blast. We don't have any need to send out blasts so I'm assuming someone from the outside got user credentials and sent out a blast.
I've looked at the reports and don't see anything unusual. Can anyone help me better secure access? I've setup MFA but not sure if this will be enough. Is there a way go get emails sent to me if any kind of change has been made in exchange or even better office 365 in general?
Also, is there a way to suspend an account if say 20 emails are sent out in a minute before Microsoft blocks us for exceeding the email threshold. I would hate having to go through this again. Does anyone know what the threshold is? I've asked but no one seems to know.
It may be more likely that the email domain has been hijacked by external spammers and so the domain has been temporarily given a "bad" reputation. Can you tell who is causing a block on them being able to send messages out ?