plesk upgrade Db error in Plesk control panel

ERROR: PleskMainDBException
MySQL query failed: MySQL server has gone away
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Additionally, an exception has occurred while trying to report this error: PleskMainDBException
MySQL query failed: MySQL server has gone away

0: common_func.php3:168
db_query(string 'select `id`,`name`,`type`,`uri` from DashboardPreset where `id`=6')
1: class.Table.php:183

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Solution:

comment the line wait_timeout in /etc/my.cnf