After struggling for 2 days to get reCAPTCHA to work on my site, I have finally found a fix. So just thought about reporting it here so it would be helpful to others, as I have seen this question a lot here, but no fix.
Problem: reCAPTCHA displays properly, validates properly, but shows error "Please complete the anti-spam verification" when you click submit button on any form registration / question / comment.
Fix: Change php version to 7.4 in Cpanel under PHP Selector. I was using 7.2 php version before and reCAPTCHA was giving error.