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 ('8ca7f0a1dc60594f47636863a6250e06', -1, 1542407879, 1542407879, '36525d74', 17, 0, 0)

Line : 193
File : sessions.php