432 4.2.0 STOREDRV.Deliver.Exception:MailboxInTransitException.MapiExceptionMailboxInTransit; Failed

[PoorMens_Bravo]

Hi All,

Many thanks in advance, we had a user whose mailbox was previously in on-prem Exchange 2010 environment and then we migrated over to Office365. Now, for some reason when a mail is being routed in the on-prem environment to her mailbox in Online, the mail for some reason gets queued up inon-prem exchange StoreDriver with recipientstatus logged as:

432 4.2.0 STOREDRV.Deliver.Exception:MailboxInTransitException.MapiExceptionMailboxInTransit; Failed to process message due to a transient exception with message Cannot open mailbox and so on...

When checked with get-moverequest, got the status as completedwithwarnings.

So, looking for what could be the issue on this.

[#2]

@PoorMens_Bravo 

Hi All,

Adding a dimension to the above issue, the migration was recently done in August and since then user had reported issue related to mail-flow, but today she reported stating that she cannot access mailbox in Outlook/OWA and the error she got was 

"the mailbox isn't available. this may have occurred because the license for the mailbox has expired"

That's scary!!

SO, checked and found that license was assigned over to the account, but, Exchange Online (Plan 2) was unchecked. Very surprising, as licensing is automated in our infra, and so checked on on-prem Exchange and found the mailbox there as well for this user. That's very strange!!!

So, mapping all the dots, could realise that the move corrupted the on-prem mailbox, and so disabled the mailbox and enabled a remote mailbox, I hope this fixes the issue for the mails that are queued up in Store Driver.

[#3]

Hi All,
Though I mentioned about the work around resolution i did to take care of the issue, I am interested to know more on this issue, looking for more inputs, do I have to add more tags??