Yes why lost conection database.. attacks Ddos or UDP reduce your internet conection and have lost conection database..
or have this error.. in database player ID 451 have in online - more 0 - 1, etc.. try add
SQL:
update players set online = 0;
need have shutdown server.. for save
or
SQL:
UPDATE players SET online = 0 WHERE name = 'accountname' LIMIT 1
search ID 451 in players.. and player look account and see what account have for changed accountname in query