2013 - Lost connection to MySQL server during query

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '9k8grvlbbgfqv3tqkd2fkgf274', '18.218.156.35', '1714968580', '1714968580', '/shop/product_info.php?info=p2134283130_Holzfass-150-Liter-Fasshaelfte-als-Miniteich.html&XTCsid=eu8qkencd38mn4khb4bk57edc4')

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = '9k8grvlbbgfqv3tqkd2fkgf274'

[XT SQL Error]