I was experiencing an issue where I could connect to the internet and the Nintendo store, but I couldn't do certain in-game activities that require an internet connection. The error code I would get is: 2618-0583 and the message was "Unable to connect to the other console(s). NAT traversal process has failed." At the time, my EeroOS was version 6.2.0. To resolve the issue, I did the following:

1. Turn off Band Steering and WPA3 from Eero Labs (Eero app > Discover tab).

2. Clear registered network on the Nintendo Switch (Home > System Settings > Internet > Internet Settings > [Your Registered Network] > Clear Settings).

3. Re-register your network. It should be listed at the bottom of the list under Networks Found.

Once I did this, everything was working again. Also, turning off WPA3 resolved other issues I was having with other devices where they could not connect to the internet at all. Such devices included an older '15 Vizio TV and a 2nd generation Apple TV. I spent months researching for a fix, but I couldn't find anything. Hopefully, this info helps someone else!

Was having this issue today and figured out the solution. On the switch I was getting an error that was complaining about a possible DNS error, but connecting games via online worked just fine. To fix this, I went into the eero settings>Newtork settings> DNS and set to "Custom DNS" and copied in the DNS setting for Google's public DNS:

IPv4 Primary: 8.8.8.8

IPv4 Secondary: 8.8.4.4

IPv6 Primary: 2001:4860:4860:0:0:0:0:8888

IPv6 Secondary: 2001:4860:4860:0:0:0:0:8844

https://developers.google.com/speed/public-dns/docs/using