Our setup is we have 2 domains: Domain A (User Domain) & Domain B (Resource Domain including Exchange Hybrid Servers). We also have Office 365 that Sync's with our user domainA and use's the UPN of that domain to connect to it.
Our Users in Domain A have a UPN of user@mycompany.com.
For our base users we create them a mailbox in Office 365 and that works fine by using Outlook. However when we have to create a mailbox in the Resource domain (for lower bandwidth sites) we create them on their local Hybrid Exchange 2013 Server.
They remote users connect to their mailbox through Outlook by the use of a linked mailbox and use their LinkedmasterAccount credentials (DOMAINA\username). This works fine.
Now it is company policy that due to low bandwidth any of the mail when they change roles \ jobs and move to back Office 365 we will delete their mail in their mailbox before we move it. However critical mail that they want to keep can be kept in their Online Archive. We create these 'hybrid' mailboxes with an Online Archive in O365. This will then be moved into their O365 mailbox after the move to access it as normal.
The issue is when they are in this hybrid setup and their mailbox is on the Exchange Server. They cannot open their Online Archive through outlook. It states:
"The set of folders cannot be opened. The attempt to log on to Microsoft Exchange has failed."
My thinking is that due to the user's Outlook connecting to Exchange with the LinkedMasterAccount credentials, in the DOMAIN\username format, that it cannot logon to O365 to access the Online Archive as this needs to be their UPN username@mycompany.com. We know that we can't connect to the Mailbox on the Exchange Server with the UPN from Outlook as we are forced to use DOMAINA\username to logon to it and not use the UPN as this keeps on prompting for the password when we try. It doesn't seem to pass through the UPN of the user to open the Online archive so it can't connect to it.
The user can however open OWA and see the online archive available so it isn't a permissions \ licensing issue.
Can you confirm that this a supported setup for accessing an Online Archive. I haven't been able to find anything anywhere stating this setup. Can the mailbox location be at a resource Domain B and the Online Archive be in O365 which uses a UPN from the User Domain A to normally access it?
Also if this is supported how can we get Outlook to logon to Office 365 with the UPN for the purpose of accessing the online archive?
