Can't update my SYNC 3 version
 

I am trying to update my SYNC 3 version on my 2016 Mustang GT. I tried to do it through Wi-Fi, but it won't update that way so once I tried to download it to a USB through the Ford Owners website, it just gives an error message saying the "service is currently unavailable." I'm trying to get CarPlay on my radio, but Ford really isn't making it easy.