SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: DELETE FROM bb2_sessions WHERE userid='0' AND ipaddress = '3.219.31.204' AND useragent = 'CCBot/2.0 (https://commoncrawl.org/faq/)'
mysql error: Incorrect key file for table './c4fboard_wbb2/bb2_sessions.MYI'; try to repair it
mysql error number: 126
mysql version: 5.1.73-log
php version: 5.6.3
Date: 02.12.2020 @ 17:35
Script: /formmail.php?userid=21
Referer: