Add captcha to Contact area in Homepage

If I try to activate the captcha control for Contact area in Homepage, the page crash.
I have activated without problem the Google "Are you robot" for login and register. Can I use this in the Contact are in HomePage?

Hi,

How exactly did you activate the captcha for the contact section on homepage?
Maybe there's some conflict with your existing captcha plugins, do you have any error messages, white screen? Could you send me a PM with backend and FTP access also?

If I activate captcha on Contact the website do not load any part of Homepge.
You have already the backend access...
I cannot give you the FTP access because I have not this login data: I am only the manager of artist...

Yes, I have the backend access, but without FTP I can't debug this problem. I need to change some files, check the effect etc.
Try to disable your other captcha plugins, then try to activate the captcha on Contact form.

Not works.
I will add an "question challenge" field...