reCAPTCHA failed request more than passed request

Question

I am using Google reCAPTCHA for form validation. I have got many customers complaint the image selections are too difficult. From the Google reCAPTCHA report, I saw the failed request more than passed request. Is this common? So question here,

1. Is there a way to monitor this kind of situation or improve it?
2. If I stuck into the image selection, is there any way I can get back to normal tick captcha?

Thanks.

You can get the details from the picture, the fail is more than pass.

Picture for spam index and average response time:

Answer 1

1. You can tune the difficulty in Security Preference, under Advanced Settings of the reCAPTCHA settings of your site.
2. Not really, since image selection only appears when reCAPTCHA thinks the tick is not enough to determine the user is a human.