SMTP Relay to Office 365 Public Folders

anybody work in a Hybrid Exchange org where on-premises Public Folders were migrated to Office 365?  SMTP relay from on-premises apps to Exchange 2010 will relay to any Office 365 mailbox... but when the app tries to send to a mail-enabled Office 365 Public Folders (via the exact same Exchange 2010 on-premises server), it fails.. any ideas?
K BAsked:
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Hasin Ahmed ChoudharyExchange AdministratorCommented:
Does it give NDR message? If email is stuck in the queue on SMTP relay server, do you see any error?

Could be authentication issue and mail PF have "Require that all senders are authenticated" selected.
Vasil Michev (MVP)Commented:
Run a message trace to get a better understanding of what happened:

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Hasin Ahmed ChoudharyExchange AdministratorCommented:

Article applies to on-premise PF.He has already migrated to Office365.
K BAuthor Commented:
Microsoft is saying you have to create contacts with external email addresses (with the PF's onmicrosoft address) ugh!
Hasin Ahmed ChoudharyExchange AdministratorCommented:
Make sense. PF hierarchy will be in cloud.
Todd NelsonSystems EngineerCommented:
Sufficient information provided for resolution.
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