Can't log in to Dashboard since upgrading SQL dm from 10.4 to 10.5

Since upgrading SQL dm from 10.4 to 10.5 neither my fellow administrator nor I can log in to the Dashboard, both receiving the message:

The user name or password you entered isn't correct or you do not have permissions to any product. Contact your administrator to make sure you have permission to access the Idera Dashboard.

When I look at user security in dm it shows that all the users but one are of the System type and cannot be edited. Most are service accounts and all have Web application access checked, all are Windows users or groups, all have Administrator permission and all have access to all servers. Yet none of us can log in.

Does anyone know what is wrong and how we can fix it?