Error Log

Also, is SSL enabled on your site? One of the error messages looks like there is an issue with your SSL certificate:

OpenSSL Error messages: error:14090086:SSL routines:ssl3_get_server_certificate:certificate verify failed

So that would be the first thing to check, make sure your site’s SSL setup is correct and without errors. Once there are no SSL issues, those other warnings/errors also should disappear.

Another thing I see is the Google reCAPTCHA error:

Google reCAPTCHA: invalid-json

Is the USP reCAPTCHA enabled and/or working properly?

What about SSL issues? Is your site SSL?

So then the only other two errors are in regards to file_get_contents(). So, do you know if there are any issues with file_get_contents() on the server? I.e., is the server properly configured to support file_get_contents()? You can ask your web host if no sure.

That error message means that the Google reCAPTCHA field was answered incorrectly. Or it could mean that there is something that is preventing the captcha field from working correctly.

I’m not sure what is happening (it is impossible to “guess”), but it sounds like there is some issue with the reCAPTCHA field. If this is the case, the best thing I can recommend is to disable the reCAPTCHA field and/or use the text-based Challenge Question instead.