1366 - Incorrect integer value: '' for column `agentur`.`whos_online`.`customer_id` at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '3vac1l80to5i5t897mnv08dkq1', '3.235.101.50', '1601424100', '1601424100', '/index.php?cat=c88_Heiter-bis-To--776-dlich---Zwischen-den-Zeilen.html&XTCsid=2d4qg7ftupcpr3opjmmv969b12')

[XT SQL Error]