Is anyone else receiving an error code when they try to visit another island or have someone visit theirs? I tried changing the DNS settings but that doesn't seem to do anything, and the only thing I've found that works is to delete and reinstall the game. Worked fine for a bit, but now it is randomly happening on another system. Any ideas on why this is happening or how to fix it without reinstalling?

By local do you mean you are both on the same wifi network?

Same wifi network, but specifically disconnected from the internet.

What is your wifi setup like? Are you on your own wifi coming from a router/WAP you own or control? Or are you on someone else's network, especially a guest wifi network?

I think local play refers to local wireless, which does NOT use wi-fi.

Ok I didn't realize that, I just looked up how Switch local wireless works and I didn't realize they could connect to each other in an ad hoc network.

Its been a feature in Nintendo consoles since the DS

Yup, it's just local wireless, not wifi (which is my own network btw). When speaking with Orville, I get get far enough to select the other island but after choosing it, I get the error message. Seems like reinstalling is the only option that works so far

Are both Switches up to date, both copies of the game up to date, and both have the same system time? I'm not sure how exactly the Switch handles things but different date/time between 2 devices can sometimes cause networking headaches.

Yup, both switches are up to date, games are the latest versions, same time, etc., which is what makes this such a mystery for me.