Content printing twice and recaptcha plugin not working

I’m using Grav for the first time and I got a problem with the contact form in my website. This contact form is generated by the reCAPTCHA Contact v2.1.0 plugin. The first problem is that when the recaptcha plugin is on (in my header), my block content is printed twice: Capture
The second problem is that I’m not able to send any mail with the form.
Does anyone can explain me why?

Thanks for your attention,

Not familiar with that plugin (so not sure what’s the issue), you might get a better result by opening an issue on that plugin’s Github issues page.

Also, the official Form plugin has built-in support for captchas too, see the example contact form.

I check this, thank you!