SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.1.3): Invalid SQL: SELECT a.replycount AS replies,a.boardid AS boardparentid,a.threadid AS threadid,a.topic AS threadname FROM bb2_threads AS a,bb2_boards AS b WHERE a.boardid = b.boardid ORDER BY a.replies DESC
mysql error: Unknown column 'a.replies' in 'order clause'
mysql error number: 1054
mysql version: 5.7.25
php version: 5.6.40
Date: 11.05.2024 @ 16:09
Script: /forum/statistik.php?sid=bb3cba6089d432aa17b5b359e71aa6ef
Referer: