phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO forum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('c5f4c46bea0f20908bfb8ca53db088ba', -1, 1539989613, 1539989613, '36e09618', -11, 0, 0)

Line : 187
File : sessions.php