Destiny 2 Port Forwarding. One of them is what ports you need to forward in order to get an open NAT. The ports are different for consoles and PC so be sure to follow the appropriate guide.
It is not recommended to enable both UPnP and Port Forwarding at the same time. Some of the problems that a port forward is know to fix are Players should only use Port Forwarding when they cannot use UPnP and are having issues playing Destiny. It's super simple and easy to do.
You're going to need a few extra details about your system before you can do that, though.
It's super simple and easy to do.
It is not recommended to enable both UPnP and Port Forwarding at the same time. One of them is what ports you need to forward in order to get an open NAT. What matters for your Destiny experience is that your NAT Type is set correctly.