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: 20.05.2024 @ 18:06
Script: /forum/statistik.php?sid=630f4e10b575103760d5706acb3196f1
Referer: