IPN Faulty

[Samurai Legend]

I am running my site on AlmaLinux NGINX. I feel like my server is not allowing any information to come from PayPal. Could this be I need to whitelist PayPal? If it is how do I do it

I get the error 

Fatal error: Uncaught Exception: Missing POST Data

#0 /var/www/public_html/ipn/notify.php(46): PaypalIPN->verifyIPN()

#1 {main}

  thrown in /var/www/public_html/ipn/ipn_listener.php on line 64" while reading response header from upstream, client: 86.150.54.9, server: samuraiconflict.co.uk, request: "GET /ipn/notify.php HTTP/1.1", upstream: "fastcgi://unix:/run/php-fpm/www.sock:", host: "samuraiconflict.com"

[AdamHull]

What the code on line 64 of ipn listener

[Magictallguy]

It's one of the IPNs I wrote - attempting to load the file directly will result in this error as there's no POSTDATA being sent on a standard GET request for loading a page in browser.
Use PayPal's Dev Sandbox to simulate real-world payments