Came across a strange one last week. IAG 2007 with SP2, ActiveSync trunk, using an Active Directory Repository.
Working fine for pretty much everyone, except one user, who is getting constant prompts from the Windows Mobile device to ‘correct your password’.
IAG is showing an authentication failure, and is logging the correct username and domain, which only really leaves the password.
Further investigation determined that the user had a # symbol in their password. When the password was changed to one without a #, ActiveSync started working fine.
I’ve since tested a non-IAG ActiveSync installation with a password including a #, and it works fine, which suggests that IAG is the problem.
I’ve now got a ticket logged with our IAG vendor, and I will post again here when I’ve worked through the issue with them.