Edit: This worked for me, hopefully, it works for you too!
Make sure your date and time is synced with the internet settings.
To do this, go to settings>system>date & time
You will see a little button/switch just make sure that is on.
That worked for me!
We have checked the epic forum to no end, but some of us here are still having issues with Fortnite matchmaking on Switch. Just seems like something that has to be fixed on Epic's end. Just kind of irritating that they are claiming everything is fixed when myself and so many other people are still having issues where matchmaking does not work at all. We cannot get into games!!
Was looking forward to reviewing the experience on the Switch, but unfortunately, at this point, I haven't been able to play even a single game.
Here is the exact error message we are getting:
We had trouble talking to the matchmaker. Give it another shot, but if the problem continues, check out http://status.epicgames.com
Needless to say, checking that site is what gave us the frustration in the first place. They seem to be saying it can be fixed by logging out and logging back in. As annoying that, we tried it. It didn't work.
Please Epic! We just want to play!