Unable to access Plesk with the 500 error: Uncaught Zend_Config_Exception: Error parsing JSON data

Symptoms

• Unable to access Plesk GUI with the 500 error.

• The following error can be found in the file /var/log/plesk/panel.log:

  PHP Fatal error: Uncaught Zend_Config_Exception: Error parsing JSON data in /opt/psa/admin/plib/vendor/plesk/zf1/library/Zend/Config/Json.php:136
  Stack trace:
  #0 /opt/psa/admin/plib/Plesk/Config.php(267): Zend_Config_Json->__construct('{"serverSetting...'

Cause

The corrupted file /opt/psa/admin/conf/leika.conf.

Resolution

1. Log into the server via SSH.

2. Rename the /opt/psa/admin/conf/leika.conf file:

   # mv /opt/psa/admin/conf/leika.conf /opt/psa/admin/conf/leika.conf.back

3. Run the following command on the command line:

   # plesk bin license --retrieve