Connect to your server via SSH.
and remove System temporaty files:
rm -rf /tmp/*
Delete files that are older than 12 days from the /tmp and /var/tmp/ directories:
find /tmp -type f -mtime +12 -exec rm {} \;
find /var/tmp -type f -mtime +12 -exec rm {} \;
Delete temporary files created by Plesk and its services. Files in the directories below can be safely removed.
Note: We recommend to run these commands when the system is idle (No active Plesk backup and Plesk Installer tasks).
To check if Plesk Installer is running, run the following command:
ps aux | grep install | grep -v "grep"
No output means Plesk Installer is inactive.
To check if any Plesk backup task is running, run the following command:
plesk sbin pmmcli --get-tasks-list Backup | grep working
No output means there are no active backup tasks.
Temporary Plesk backup files:
rm -rf /usr/local/psa/PMM/tmp/*
Other temporary files:
rm -rf /usr/local/psa/tmp/*
If that does not work restart your apache.