Contact form is not workink, but it is on a staging site

Hi,
First apologize myself because I send this on a contact email.

My problem is that on my main site my contact form 7 stopped working properly on 1st novemmber. I made a staging site, and there’s working perfect. I tried to backup, but nothing, and I tried to speak with the hosting, and they say it’s all okay.
The thing is: why it’s working on the staging site? the sender is the problem?

Thanks,