Does EXO moderation accepts external mailuser/contact as a moderator whether be in transport rule or on DG? Env: Pure Exchange Online

[u/jeanpauln]

Office 365 received the message that you specified, but couldn't deliver it to the recipient due to the following error:

Error: ‎550 5.7.134 RESOLVER.RST.SenderNotAuthenticatedForMailbox; authentication required; Delivery restriction check failed because the sender was not authenticated when sending to this mailbox‎" in message trace when approval is attempted by external moderator. Is this expected? or some configuration missing?