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 ('875fd8d0538662a2e4b57883d27bb0ed', -1, 1781122247, 1781122247, 'd849d92f', 2, 0, 0)

Line : 189
File : sessions.php