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 ('24c3f98321a98544d51d3153188dca5b', -1, 1550659017, 1550659017, '345bb0fb', 26, 0, 0)

Line : 187
File : sessions.php