Excluding shared mailbox from DLP policy

[Gurdev Singh]

We have excluded a shared mailbox from DLP policy via a distribution group. DLP policy is defined in Compliance center. However, emails being sent to this mailbox by external senders are still being blocked.

Anyone know why DLP is still blocking emails from reaching the mailbox even though it's being excluded from DLP scope. We need this mailbox to receive emails from outside senders. 

[#2]

DLP only acts on outgoing messages, so I'd wager it's something else causing this. Have you run a message trace, check the details there: https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/message-trace-scc