I'm setting up a new Exchange 2013 org. Everything is pretty fresh, only a few mailboxes have been added for testing.
I've added this permission, to provide full access to all the mailboxes in the database:
Get-MailboxDatabase -identity Mailbox Database | Add-ADPermission -user netadmin -AccessRights GenericAll -ExtendedRights Receive-As, Send-As
I've verified the permission in ADSI Edit.
I have verified the permission in the recipient's mailbox delegation properties.
However, while logged into OWA using the admin account, if I try to open another user's mailbox from OWA, I just get a sad face that says "Something went wrong :( " .
Any ideas? I've tried resetting the owa virtual directory...reset IIS, rebooted several times, no luck.