SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: SELECT hsp.topic, hsp.threadid, (SELECT value FROM bb1_hsp_rating WHERE user_id = 15 AND hsp_id = hsp.threadid) AS hsp_value FROM bb1_threads hsp WHERE boardid = 89 ORDER BY hsp_value DESC, hsp.topic ASC
mysql error: Subquery returns more than 1 row
mysql error number: 1242
mysql version: 10.1.26-MariaDB-0+deb9u1
php version: 5.4.45
Date: 20.05.2018 @ 13:57
Script: /profile.php?userid=15&action=hsp_rating&serie=89
Referer: