Exchange Online - I can't send external mail messages

Question

When trying to send emails to external domain via email 365, I got the following error "access denied, traffic not accepted from this IP."
Has anyone ever experienced this ?

Answer 1

Hello Marcel follow this documentation for solve your issue

You need to open support ticket

https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-online/fix-error-code-5-7-700-through-5-7-750#57708-access-denied-traffic-not-accepted-from-this-ip

5.7.708 Access denied, traffic not accepted from this IP
This error can happen when you are trying out a Microsoft 365 trial tenant. If you receive this error before you can purchase licenses, contact support to request an exception for the low reputation IP address until you're able to purchase licenses.