Hello Michael,
I've answered to your earlier post that were related to the captcha issue. Please see this post:
No submit with active reCaptcha

I apologized for the delayed respond.

I have a similar Problem. A form with activated reCaptcha v3 is not submitting, only the form is reloading in empty state. If I deactivate the Captcha the form is send properly, stored in database and the email is send.

you may want to analyse the source: www.kgv-sonnengrund.de/index.php/bewerbungsformular (sorry, page is in german)

reCaptcha plugin is configured properly as far as I know, keys are all new...

That's great!

Can you clarify what you did to solve the issue?
I will pin your answer for other users who might come across this issue in the future

It seems to work now! Thank you
I will try to solve the capycha problem.

I visited your site and tested your form, it seems like there's an error on the captcha initialization. You can see the error when you load the page with a browser console open (Option+Command+I on Firefox).

Let's try narrowing down the issue. Can you try removing the captcha from your form and see if the form can now be submitted?

I tried to put the form in a published page ( www.indomoassistenza.it/lavora-con-noi ) and now, when I submit, the page make a refresh but no email sent (and no email recived) and no messages appear (no error nor submission message)