Disconnection changing zones

I'm trying to play with a friend of mine and he constantly gets disconnected from the game when changing zones... but not all the time. It doesn't make sense. He doesn't want to come to the forums so I'm looking for some help with this for him.

Are there any solutions for this?? We've tried

--noasync
Switching gateways
Switching GPU settings
Changing display settings
Switching DX11/12/Vulkan
Reinstalling the game
Downloading from PoE site vs Steam
Disabling firewall/adjusting firewall settings
Updating computer/drivers

Specs
NVIDIA RTX 3060
Processor - i7 1300 series
SSD storage
64GB RAM 5th GEN

Can ANYONE help with this? This seems to be a big, long-running issue that doesn't have a solution easily found online.