For any poor saps who find this post...
First of all, that error message gets displayed for pretty much everything. Guess BIS devs got a bit lazy, but it can mean wrong password, username, mailbox, etc.
My problem was that I was trying to setup an OWA account that did not have an @company.com email address in AD, they had @someothercompany.com (it was a company buy-out; one employee assumes the identity of
and didn't want their accounts mixed up in Outlook so I created a new AD user/mailbox; another long story but IMAP is your friend when you want to have two Exchange mailboxes open at the same time).
What I had to do was create an email address for that other AD user that matched the AD account name I'm trying to setup in BIS.
So in my case, I had created an AD account called "soc-info" which had only
as an address.
To fix it, I added
as an address in the AD Email Addresses property, even though I have no plans of using it (in fact my spam filter drops mail to that account as I don't even want it used).
I then when into the BIS account and edited it to reflect the real address I want to use as well as setting the reply-to address to
; no complaints there, saved without issue.
Now, I'm suspecting that the form validator doesn't like that your email address is different than the OWA URL specified and/or that your username doesn't match the local part in the email address, but I haven't verified it.
Having thought about it, I bet I could've added any OWA account then gone back in and edited it to what I wanted.