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 ('dbec3c75cd7e6d0a685cce654ffc44ef', -1, 1539948086, 1539948086, '36e11a2c', 12, 0, 0)

Line : 187
File : sessions.php