My friends nintendo switch keeps saying “Network communication error.” while playing using nintendo online. Can anyone help?

I'm hoping someone can help find a solution to a problem that a friend of mine is having. Me and 3 others have been trying to play Mario 3D World using Nintendo Online but, one of my friends has been having a problem with her Nintendo Lite. Every time she connects online, every 3-8 minutes she gets an error message saying "Network communication error." She is the only one having this issue. I had her first restart her Switch to see if that worked, it didn't. I had her try restarting her router, setting her MTU to 1500 instead of 1400, setting the DNS primary to 8.8.8.8 and also 1.1.1.1, and clearing her cache. All of which did not fix the issue. I had her run an internet test on her switch, and her NAT type was B . Nothing indicated that there was a problem. I also had her try connecting to her mobile hotspot, and playing that way, the problem still persisted. Because of that, I thought maybe it was the nintendo switch servers in her area, so we tried the next day, and the problem still remained. I've honestly run out of ideas on what to do. Have any of you guys had this problem?