phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('aeef57542181754b546dcc6e747a2c7f', -1, 1711668047, 1711668047, '36dd2b9b', -4, 0, 0)

Line : 187
File : sessions.php