Failed to start the "psa" service

[Rollioz]

hi,

Need your help guys. Im new to vituozzo and plesk.
One of our container is having a problem with plesk.
Upon checking on the plesk panel server and session link on the left panel disappeared.
I've checked on the containers system services found out that the psa service is not running.
When I try to start it up I got this error:

Failed to start the "psa" service.
Cannot start/stop/restart service: service "psa" status is not "running" after command "start"

When I checked on the plesk version it was updated from 8.6 to 9.0.1 which the container admin might have installed.
All of our plesk is running 8.6 for now.
Is this a Plesk license key issue when it was updated? or its nothing to do with the license?

thanks...