A bit of advice for BlackBerry admins of BlackBerry domains with BlackBerry Administration Service (BAS) high availability.
You should not restart all the BAS instances at the same time or shortly after each other. Some of the BAS instances might not startup correctly.
Best practice is to stop all BAS instances and bring the BAS instance you want to have the cluster singleton role up first and wait until this instance has returned to a state where you can logon to it. Normally this is when the BAS-AS.exe process is using about 700 MB of ram or more.
If the BAS-AS.exe process stalls when starting for a minute or longer at using an amount of ram below 700 MB there is a problem. You should investigate the BAS-AS logs for any clues to the cause.
Determine which BlackBerry Administration Service has the singleton role (KB22609)