prlctl command produces an error :
~# prlctl list Error message:Login failed: Unable to connect to the server. The maximum number of simultaneous logon attempts has been reached. Try to connect to the server later.
PSBM 5 bug PSBM-22493.
The issue will be fixed in the future PSBM updates.
As a workaround, it is possible to restart Parallels Dispatcher service. Note that this action may stop all running VMs (depending on their autostop/autostart settings)!
~# service parallels-server restart