Not sure if this is the right place to mention this, but it's the best I could find (i.e. no 'webmaster' contact link).

The page https://www.tixati.com/donate/  on your website states:

"PayPal Secure Payments   Quick and easy, any credit card accepted, no PayPal account needed"

This may have been true at one time, but it looks like a PayPal account is now required, so you may want to update that.

I just tried it and didn't need a paypal account, but I think sometimes it locks out certain IP ranges and only allows PP accounts to work from them.  If you are on a VPN I think it can happen (not just on Tixati, but PP donate buttons on any site).

The Tixati people need to setup an alternate CC processor like Stripe... too bad the cryptos aren't more widely used / practical yet.