Paypal IPN Handler: 400 Bad request

Finally solved with this contribution

https://github.com/nopSolutions/nopCommerce/commit/ef14689a45b455a8eb960b146f8b86fbee3ebbeb

Thanks and please close topic.

Awesome!  I mentioned that at the bottom of this post (sorry I was not able to help with better testing) : https://www.nopcommerce.com/en/boards/topic/84852/paypal-ipn-handler-400-bad-request#270212