Hi!
We've just upgraded from our old Domino email server to Office 365 E1 and running an on-premise Exchange 2013 hybrid server.
In Outlook 2013, when trying to expand a shared mailbox, It asks me to enter my outlook credentials. Trying so doesn't work and it continues to ask repeatedly. If I click cancel, I get the following error:
"Cannot expand the folder. The set of folders cannot be opened. Microsoft Exchange is not available. Either there are network problems or the Exchange server is down for maintenance."
The error only occurs in Outlook 2013 and it happens to all staff who are using Outlook 2013. Shared mailboxes are accessible in Outlook 2010 and OWA with no issues.
I have tried recreating profiles, removing and re-adding permissions, disabling auto-mapping. I've tested with creating shared mailbox in Exchange Online and on our hybrid server.