SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: SELECT * FROM bb1_info_charaktere WHERE (synchronsprecher = 'Helmut Gau��' OR (synchronsprecher LIKE '%Helmut Gau��%' AND synchronsprecher LIKE '%;%') OR synchronsprecher LIKE 'Helmut Gau��%[%') AND synchronsprecher != '---' AND synchronsprecher != '-hb-'
mysql error: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_unicode_ci,COERCIBLE) for operation '='
mysql error number: 1267
mysql version: 10.5.15-MariaDB-0+deb11u1-log
php version: 5.6.40
Date: 14.08.2022 @ 05:42
Script: /hoerspiele.php?action=search&syn=Helmut%20Gau%EF%BF%BD%EF%BF%BD
Referer: