Resolution
To increase timeout for operations with Plesk nodes (setting Plesk domain/client properties, provisioning, fetching information from Plesk nodes) you may adjust SHORT_TIMEOUT variable in /etc/hspc/hspc.conf configuration file inside HSPcomplete VE (it is set to 300 seconds - 5 minutes by default) and restart HSPcomplete backend to apply changes:
# grep SHORT_TIMEOUT /etc/hspc/hspc.conf
SHORT_TIMEOUT = 300
(adjust the limit with increasing it up to 600 - 10 minutes)
# grep SHORT_TIMEOUT /etc/hspc/hspc.conf
SHORT_TIMEOUT = 600
# /etc/init.d/hspcd stop
# /etc/init.d/hspcd start
Keywords: timeout