phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '78a98dc47d27a3de4c3fc557af3195e6' 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 ('78a98dc47d27a3de4c3fc557af3195e6', -1, 1768807412, 1768807412, 'd849d879', -4, 0, 0)

Line : 187
File : sessions.php