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 ('88443d493b3edacc3d6cdab1784a2761', -1, 1561462811, 1561462811, '22cc2465', 28, 0, 0)

Line : 191
File : sessions.php