The loading issue might come from the browser itself. Too much cache build-up on it can cause unexpected behavior with the product.
Let's run some basic troubleshooting steps so you can get back to your business.
To start, access your account in a private window. This will help us determine if the issue is cache-related. Simply press the following shortcut keys to open this mode.
Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
Once done, go back to the VAT window. If you're able to open it, clear the cache in your regular browser. You can also use another supported browser to view your VAT details.