Unable to join multiplayer on PC only.

We are unable to connect to multiplayer on PC. I get Kelp error. I have reset firewall rules and readded Minecraft. I have turned off firewall and still get Kelp error. It will randomly let us join each other once. Then it’s back to Kelp error. We have 2 Alienware M18 R2 PCs with 64 gigabytes of RAM, 16 gigabyte of video RAM, terabytes of SSD free disk space. We own the following that work and we can join each other: Switch, Switch 2, iPad, iPhone, Android 16. PC starting with version 26.0 to 26.2 will not let us join each other. We are wired to the same router. We are not using wireless. We had a friend miles away attempt to join us and it does not work. I have uninstalled and reinstalled many times on both PCs. Please help. We are both running same version of Minecraft 26.2