We are having an issue where all of our public folders recently stopped receiving email from external users; internal users can send to them fine. The problem started yesterday and I have made no changes. The NDR is saying it's a permissions issue:
BN1PR05MB026.namprd05.prod.outlook.com
Remote Server returned '550 5.7.1 RESOLVER.RST.AuthRequired; authentication required [Stage: CreateMessage]'
Our employees mail is unaffected and in looking at the mail trace within O365, it shows some messages to the public folders failing and others "delivered" yet nothing is showing in the folders which makes me think this is an O365 issue. We ran the command to allow anonymous to CreateItems for the public folder and am waiting an hour for that to fully replicate yet I don't think that will resolve the issue. We've also set the accepted domains to...