Paypal INVALID IPN Response

.. Continuation of the issue raised on github.

https://github.com/opencart/opencart/issues/2750

The reason why your status is the default "Pending" is because the IPN Validate response is "INVALID".

Here is some help in regards to that
https://developer.paypal.com/docs/class ... g/#invalid

My guess is you need to update your paypal encoding to be UTF-8.