PixelAnne  Please try again now, and try store.thesims3.com if the first one doesn't work.  I've tried a couple times today and had no issues.

For the blank launcher, please clear Edge's Internet Explorer-mode data.  Even if you never use Edge, the launcher does for a few purposes.

https://support.microsoft.com/en-us/microsoft-edge/view-and-delete-browser-history-in-microsoft-edge-00cf7943-a9e1-975a-a33d-ac10ce454ca4

puzzlezaddict PixelAnne 

I could log in to store.thesims3.com but couldn't go to my studio or the Exchange. I got the following error:

504 Gateway Time-out

I had cleared my browser date for Chrome and Edge, but I still got the error after the browser tried to connect for well over a minute. However, I just tried it now, and it took me to my studio right away, so it appears to be working again.