If such message appears, with high probability the transaction is blocked by Stripe payment system according to their business rules in Latvia. The payment system checks the IP address of transactions for affiliation to jurisdictions, that would be prohibited by US economic sanctions.
You can try different payment way or try to use any VPN to process the payment, e.g. free Browsec VPN.
I encountered an issue during the checkout process with your plugin. Could you please provide me with the payment invoice? I would like to proceed with purchasing your plugin.
Helped via email.