When I submit it I get the same error I got a few weeks ago from one of the Halloween themed SBC, that others also complained about.
"We are sorry but there has been an error connecting to FIFA 19 Ultimate Team. You will be returned to the FIFA 18 Main Menu."
This is a 24 hour SBC. I have very little faith you will fix this in time, but you really need to get your S* together and put more attention into making sure that Switch content works. We already have little enough as it is. You aren't making a good case to refresh this title next season.