SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: SELECT DATE_FORMAT(zeit, '%d.%m.%Y
%H:%i:%s'), nachricht FROM ragnarok.fro_gmmessages ORDER BY zeit DESC LIMIT 20
mysql error: SELECT command denied to user 'forumDNA'@'localhost' for table 'fro_gmmessages'
mysql error number: 1142
mysql version: 5.6.38
php version: 5.6.30-0+deb8u1
Date: 11.12.2017 @ 18:10
Script: /mob_showLastGMMessages.php
Referer: