Assuming these are HTTP error codes you received (You attempted something on their website) and a 401 means Unauthorized and the 601 means Server overloaded / Refused (An obscure code as it's typically something else). It could be that their purchasing service is down. You could attempt to connect to Google's Public DNS and do an ipconfig /flushdns (Windows Key + R type in CMD hit enter and type the command).

Instructions for connecting to Google's DNS: https://developers.google.com/speed/public-dns/

If your lucky this will put you on a different instance of their servers and it might go through (kind of like picking a server for FF14).