MyBB SQL Error

MyBB has experienced an internal SQL error and cannot continue.

SQL Error:
144 - Table './lg/mybb_posts' is marked as crashed and last (automatic?) repair failed
Query:
SELECT u.uid, u.username, COUNT(pid) AS poststoday FROM mybb_posts p LEFT JOIN mybb_users u ON (p.uid=u.uid) WHERE p.dateline>1711629323 GROUP BY p.uid ORDER BY poststoday DESC LIMIT 1