Solution
FocalPoint is licenced for a certain number of users, depending on the licence you have purchased.
When you reach this limit, you will not be able to enable any more users - which is what happens when you add a user to a new Security Profile.
You will need to disable any enabled users that no longer need access to free up some licences, or if there is no one whose access can be revoked, you will need to contact your account manager to purchase a new licence.
To disable a user who no longer needs access:
Log into FocalPoint Admin
On the System Control tab, click Users
Find an active user with a tick in the Enabled field.
Click the Edit icon
Clear the Enabled check box
Click the green tick, Save icon.
Note - you will need to ensure that you are below your licenced limit before you can enable a new user. Sometimes the licence limit might have been exceeded by several users and so you will need to disable more than one, to get below your limit again.