Im not able to see mailbixes on the cloud o365, i have hybrid on exch 2103 this happend after upgrading to 2019

Question

exchange 2013 hybrid, about 5 servers, installed 2019 and migrated all mailboxes to news servers after adding new servers to the hybrid setup as well
no i am not able to see the majority of the mailboxes under exchange admin center
old servers are decommissioned, trying to migrate mailboxes back on prem does not work because users are not mail enabled users anymore

when i try to enable-mailuser
It throws an error that this user does not support such format

Answer 1

You meant the on-prem EAC view?

You wouldnt use enable-mailuser, it would be enable-remotemailbox

But before doing that, check to see if it already exists

get-remotemailbox <User> 

Run this on-prem and check a user you see in 365 and not on-prem.
Does it return anything when you do that?

Answer 2

Hi @Maher Ramadan ,

Yes, please check the suggestions above from Andy.

We could also check below values for your mailboxes in ADUC > mailbox properties > Attribute Editor

msExchRecipientDisplayType
msExchRecipientTypeDetails
msExchRemoteRecipientType

The meanings of the values above are listed in this link

For the command Enable-RemoteMailbox which used to create a mailbox in the cloud-based service for an existing user in the on-premises Active Directory.

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