2006 - MySQL server has gone away

SELECT content_id, categories_id, parent_id, content_title, content_group FROM content_manager WHERE languages_id='5' and file_flag=0 and content_status=1 order by sort_order

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = 'jo81m473f8kacaha5brn4okpo4'

[XT SQL Error]