I bolded the main points that I'm wondering about as well as the specifics about my specific situation.
I know that there's going to be fixes for this in the future, but I have a couple of general questions about this. For context, I have two devices. I first set up a PNID on my N3DS and it was working fine. I started to have issues connecting to the server after I set up a second PNID on my O3DS. I locally friended my own devices together so I could get more plant pals for Mii Plaza: Flower Town.
All I'm trying to do is add a couple of friend codes to my N3DS that I've received, but I've been unable to get connected to do this.
I don't know if there's problems with having two devices in the same household/network, or, more likely, problems with using the same email address for two different PNIDs (it doesn't seem to be an issue cause I can log in on PC with both of them, but who knows. I sure don't.)
I have tried using my phone as a hotspot and connecting through that, I have tried setting the IP address to "do not auto-obtain" and changing the IP address, neither has made a dent in this issue; I open up the friends menu and 20 seconds later I get 001-0502.