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 ('5aa8eb009237a792a0fcdfe7cb79c824', -1, 1540260288, 1540260288, '36e0f72a', -9, 0, 0)

Line : 187
File : sessions.php