We have a couple different sites set up for personal device enrollment so that different people have access to different e-mail accounts. One site has three exchange accounts set up on it. Two of the accounts have the account/password entered in already (they are shared accounts that the end users don't know the password for) and the third uses variables since it's for their work accounts that they do know the password for.
Right around the time iOS 11 came out some users who we've had to unenroll for various reasons don't get an option to choose an enrollment site. They just get enrolled in a default site that only has their work e-mail and have no option for joining the site with the shared mailboxes. Is this an iOS 11 thing? Any ideas?