Help with setting up US Amazon for UK Seller

Hi, my company sells on Seller Fulfilled Amazon UK. We are trying to sell globally to the rest of Europe and the US. We are having trouble setting up our US marketplace. It says Registration Pending next to amazon.com when I go to select the marketplace from the drop down and when I click onto it it says I need to continue registration, when I do this, it says to wait while processing and then says it’s not working and to try again? Any advice or is it just Amazon.com having a moment?