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 ('d5642c19bd6a9a719cac4704039e0d9c', -1, 1711710611, 1711710611, '0352e81f', -4, 0, 0)

Line : 187
File : sessions.php