Cannot purchase Insight Premium subscription credits

What is wrong with the website? Every time I try to purchase device credits it gets to the payment page and says "Something went wrong" on a red bar across the top of the page. It disappears after a few seconds and then allows me to put the payment details in. When I confirm the order I'm presented with a blank page and "Session is not set" in the top left corner. Happens on all different browsers and in incognito mode too - also tried different computers. Very frustrating!