phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO docttorrdiscluc_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('6b15fda34dd0f72f621d449cf64be290', -1, 1544595008, 1544595008, '345bb931', -7, 0, 0)

Line : 190
File : sessions.php