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 ('4d007fc99258aa67eb2804f93026bec4', -1, 1513620963, 1513620963, '3652385f', -50, 0, 0)

Line : 193
File : sessions.php