I have a problem with many of our users getting the message above. We are using LDAP to authorize our users to connect. When we check their accounts in AD, the users are not locked or have any warning messages. What we do to "fix" it is to update something in their accounts and it works. I'm not sure why it keeps happening, and if we have something in AD configured that we need to change. We have two MAG's 2600 and only one of them is giving us this problem. The one that we haven't had any problems is running Windows Server 2008.
Details: 5.1 Windows Desktop Clients
MAG-2600
7.4R10 (build 30731)
AD- Windows Server 2012r2