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 ('6b3b7d6fa5955c459933b9075f9ecc70', -1, 1534582612, 1534582612, '3650d069', -2, 0, 0)

Line : 187
File : sessions.php