ReCaptcha Fail

on my gmail account, i have create recaptcha. after it, i have the codes in my contactform, now i have the message: "Fehlerhinweis für Inhaber der Website: Invalid site key"
what can i do?
greetings alex

For the recatcha, you have two keys, one is in “process”, and the other one is on the form itself.
See this example:
Make sure you provided the correct site key and I see no reasons why it would not work

If have use the example and there was the error. today i have generate a new key and set the new keys in the code. Now it works.
But where (in which folder) must i create the folder thankyou?