I am trying to pass the total camp fee on a registration form into a Pa

I am trying to pass the total camp fee on a camp registration form into a Paypal payment form with this URL in the thank you field of the registration form https://form.jotform.us/70874394087165?paymentthrough={totalcampfees}. The payment form opens correctly, but the field does not automatically fill. "payment through" is the field name for the payment form blank and "totalcampfees" is the field name on the registration form. What have I done wrong?

I saw that you posted same question on this thread as well https://www.jotform.com/answers/1106307 

Please see an answer my colleage provided you there. 

Also it should be paymentThrough not paymentthrough. 

https://form.jotform.us/70874394087165?paymentThrough={totalcampfees}