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) VALUES ('24d26af64b99870c30f82e12642f9457', -1, 1490328895, 1490328895, 'ac44417d', -11, 0)

Line : 158
File : sessions.php