Forum Discussion
Email address blocked from sending messages
We have had this happen a few times for legitimate emails and had to open a support case with Microsoft. They will likely need one of the messages that caused the issue to review headers, but are able to do something on their side to help prevent this from happening. The easiest way I've found to grab the original message with all of the details they need is to update your Outbound Spam policy in the Exchange Admin Center to send notification when senders are blocked. You will get a copy of the message that was blocked as potential outbound spam along with the alert.
If you have senders that are already blocked, you can unblock them using the remove-blockedsenderaddress cmdlet. If you have multiple that you'd like to remove in one go, you can use the info in my blog post: https://itspartlycloudy.com/2018/03/09/removing-multiple-blocked-senders-from-eop/.
@ Jeremy Miller
Thanks for your input. However that requires an email address to be blocked.
This has not yet happened on the O365 tenant of the second charity that I do O365 support for.
I need to prevent this happening as blocked emails could have a negative impact on an intended recipients wellbeing!
In the case of the first charity, we have been operating O365 for nearly 3 years without problem. Now we have had 3 accounts blocked in the past few months.
All I want is some way of preventing legitimate users being arbitrarily blocked from sending emails to external addresses.