(string) connection unexpectedly closed (timed out?)

Query: SELECT SUBSTRING_INDEX(GROUP_CONCAT(keyword), ',', 8) AS related_terms FROM search_popular WHERE (keyword LIKE 'youtube adult%' OR keyword LIKE 'youtube%' OR keyword LIKE 'adult%') AND keyword != 'youtube adult' ORDER BY hits DESC LIMIT 8
Error Message: Server shutdown in progress
Error Number: 1053