Is the $_SESSION['UserID'] variable populated correctly? And does the SQL query you’re feeding it to return any results? Adding some var_dumps to key points in the code can help you figure out why the variables are empty.
Oops i got it to work. Apparently the SQL i did using the one in MySQL can’t work for the one in epizy. Modified some things and it works. Btw suddenly my website is unable to enter and leads to a http://potatoreviews.epizy.com/?z is there any way i can resolve this.