phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '0' 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 ('9410cf4394c4d545a4bb6b8039410eda', -1, 1540090195, 1540090195, '36c6d41e', 80, 0, 0)

Line : 187
File : sessions.php