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 ('ac3132cf434ca26f03f1caeb07a86d3d', -1, 1539928381, 1539928381, '36e11a2c', 0, 0, 0)

Line : 187
File : sessions.php