License is in grace period even though it was updated/renewed correctly on a licensing server side:
Warning: You are currently operating within the grace period of your product license. To update your product license, select the Retrieve Keys option on the License Management page.
While trying to retrieve/install keys at Plesk > Tools & Settings > License Management (Plesk > Tools & Settings > Server information) the page loads forever until it fails with:
504 Gateway Timeout
The same error may appear when trying to log into Plesk.
After enabling debug, in
/var/log/plesk/panel.logit can be seen that the license update stops on the following step:
DEBUG [util_exec] [5af1e640d2247] Starting: sysinfo df-full, stdin:
df (disk free)processes can be found:
# ps aux | grep df
root 6806 0.0 0.0 18356 2012 ? S 06:46 0:00 /usr/local/psa/admin/bin/sysinfo df-full
root 7229 0.0 0.1 18356 4416 ? S 06:48 0:00 /usr/local/psa/admin/bin/sysinfo df-full
root 11409 0.0 0.1 18356 4424 ? S 12:55 0:00 /usr/local/psa/admin/bin/sysinfo df-full
root 13955 0.0 0.1 18356 4420 ? S 12:57 0:00 /usr/local/psa/admin/bin/sysinfo df-full
df -h command hangs
The "df" utility processes are hung (for example due to bug in CentOS / RedHat 7.5 in CentOS 7.5, however Ubuntu operating system might be affected too) causing Plesk services to hang too.
The issue is also registered as Plesk bug PPPM-8614 which is planned to be fixed in future product updates.
Note: it is not recommended to kill the stuck df processes.
Reboot the server to fix df command related issue. All Plesk services will work correctly when df command can be executed normally.