Some users do not see the custom payment gateways

Hello, I purchased the pro version of Custom Payment Gateways for WooCommerce. Everything seems to be working great, but I have some users reporting that they do not see the custom payment gateways on my check out page at all. They even sent me screenshots. For many people it is there and it works, but for others the two gateways that I created are not visible, but my other gateways (like PayPal and Stripe) are visible. It does not seem to be related to a certain device or browser. Is there anything that would prevent the custom gateways from being visible for users based on their location or any other factor?