phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO r2ok_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('3e0e974e264ebef8e6fca6c3a120c845', -1, 1524205762, 1524205762, '3650082c', 5, 0, 0)

Line : 187
File : sessions.php