Fix error on Wordpress when migrating a domain

Transferred a site on WP with taksoparki.ru on https://taxi-247.ru/podkluchenie/ now when creating a new page is thrown this error "Error publishing. The answer is not a valid JSON response".

Need to fix https://monosnap.com/file/6QGM6nKcbMUDkYDtajKrbXLd9iq8dy