Kernelcare extension license expired, a paid add-on license does not take any affect

Symptoms

Plesk extension key has expired, however Plesk+paid add-on license for KernelCare in Tools and Settings > License Management > Additional Licenses is active. In the extension's interface following message exists:

The following messages may be sent to Plesk administrator:

Mail subject: Cron <root@example> /usr/bin/kcarectl --auto-updateMessage: The IP 203.0.113.2 was already used for trialing on 2017-05-16No handlers could be found for logger "kcare"

The following command results in an output:

# kcarectl --license-infoYour trial license for the IP 203.0.113.2 expired on 2017-05-15

Following error may appear in /usr/local/psa/admin/logs/panel.log:

DEBUG [extension/kernelcare-plesk] [58abc79251960] Starting: '/usr/local/psa/admin/bin/modules/kernelcare-plesk/kcare_plugin_utility.sh' 'plugin-info', stdin:INFO [panel] Session 51e8fedc51ac87d7ce183ea65496e408 was not saved: not modified
DEBUG [extension/kernelcare-plesk] [58abc7934754e] Finished in 0.56546s, Error code: 3, stdout: Key limit reachedDEBUG [extension/kernelcare-plesk] [5937d2b106e27] Finished in 2.39585s, Error code: 0, stdout: --START--4Your trial license for the IP 203.0.113.2 expired on 2017-04-30LICENSE: 0True3.10.0-514.21.1.el7.x86_643.10.0-514.21.1.el7.x86_64

OR

DEBUG [extension/kernelcare-plesk] [5ea550865b28e] Finished in 1.10055s, Error code: 3, stdout: You have reached maximum registered servers for this key. Please go to your CLN account, remove unused servers and try again.

Cause

Kernel Care key was installed on more than 1 server. KernelCare generates a unique token once the license was first time used for activation. That's why the activation will not work if a license is used on more than 1 server.

Resolution

Contact CloudLinux support for assistance https://www.cloudlinux.com/support