Symptoms
The following bunch of error messages appears in /var/log/plesk/panel.log
file each hour:
[2020-04-29 10:17:23.596] ERR [extension/wp-toolkit] Request failed with status code 400, reason: License not found
[2020-04-29 10:17:23.842] ERR [extension/wp-toolkit] Request failed with status code 400, reason: License not found
[2020-04-29 10:17:24.075] ERR [extension/wp-toolkit] Request failed with status code 400, reason: License not found
[2020-04-29 10:17:24.314] ERR [extension/wp-toolkit] Request failed with status code 400, reason: License not found
[2020-04-29 10:17:24.547] ERR [extension/wp-toolkit] Request failed with status code 400, reason: License not found
[2020-04-29 10:17:24.774] ERR [extension/wp-toolkit] Request failed with status code 400, reason: The provided siteurl value is unknown.
Cause
WordPress Toolkit extension bug with ID EXTWPTOOLK-6078.
Resolution
Until the bug is fixed, the error messages can be safely ignored.