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 ('073819e4cbf6f7a62a24ba5b656d1db7', -1, 1711712108, 1711712108, '2cdcb6c6', -9, 0, 0)

Line : 187
File : sessions.php