My ASP IPN listener works great for selling products. The HTTP message is received, processed and posted back.
However, when processing a Refund the message is received and our internal process is working but the post back is not. This causes all Refund IPN messages to indicated Retrying in the IPN History.
Do I need to append the HTTP message with something different before posting back? This is what is appended for Selling:
&cmd=_notify-validate
Thank in advance for any help.
Cheers
