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 ('a2d2b55d48b80ced995ee7b1c1f30921', -1, 1711711912, 1711711912, '36915268', -1, 0, 0)

Line : 187
File : sessions.php