Can't connect to friends network

[fruit lord]

Me and a buddy of mine are having trouble connecting to each others networks it seems. In pretty much every game we play if he is hosting I can't connect, If I am hosting I can't connect. Sometimes however we can connect to each other but it will just be very very laggy. I personally have not a single clue as to how to fix the issue. This just started happening this week a few weeks ago it was fine

[Levisallanon]

7 hours ago, fruit lord said:

Me and a buddy of mine are having trouble connecting to each others networks it seems. In pretty much every game we play if he is hosting I can't connect, If I am hosting I can't connect. Sometimes however we can connect to each other but it will just be very very laggy. I personally have not a single clue as to how to fix the issue. This just started happening this week a few weeks ago it was fine

What are you using to connect to each others network and what kind of things are you hosting?
What did you set up beforehand etc?