phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' 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 ('96a747ad8b17cfaf66e5b93b85a5f94e', -1, 1544405695, 1544405695, '345b5a7a', 0, 0, 0)

Line : 193
File : sessions.php