Is there a problem with mastercard?

[Zungar-silver-hand (Zungar)]

Yes.

Can't Add payment method

What I just got from a GM: I read over your ticket and I understand you are getting an error when trying to update your card info. Currently we have a know issue affecting Mastercards. We are working on getting this fixed but for the time being using the card via PayPal will work. Otherwise using another card type at this point should also work. We do nto have an ETA on the fix but hoping it is a quick fix myself.