Recaptcha dont work on checkout

for now we disabled the plugin because it dont work on the checkout page so people cant checkout anymore if the plugin is enabled. On every page the recaptcha is working correctly but only on the checkout page not. When people click on it and select the right images it still say that the recaptcha is not correct and try again. How to solve this issue?

The page I need help with: [log in to see the link]