phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'a18fb144c636f47ce6a14822a19cac68' for key 'phpbb_sessions.PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a18fb144c636f47ce6a14822a19cac68', -1, 1771004871, 1771004871, 'd849d809', -4, 0, 0)

Line : 187
File : sessions.php