Exchange Online & OnPrim

Symptoms Microsoft Exchange Server (on-premises) users and Microsoft 365 users can't send email messages to or receive messages from one...

Symptoms When you add a new domain in Microsoft 365 portal, and you create users or change existing users to use the new domain, email...

Symptoms Mail that you sent to an Exchange Online Protection (EOP) or Exchange Online (EXO) recipient is deferred, and you receive the...

Symptoms When users request a delivery receipt for a message that they send to external recipients, they receive the following message:...

Problem You set a transport rule in Microsoft 365 to return a non-delivery report (NDR) that displays a custom message. However, the...

Problem When you try to validate an outbound connector in the Exchange admin center in Microsoft 365, the test email message isn't...