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 ('81978a0e192135f7f5ae10a8928f2e1d', -1, 1711709499, 1711709499, '2cdf2589', 6, 0, 0)

Line : 187
File : sessions.php