One of our clients site is facing an unique problem, whenever we click on the SERP result in google for our client site the url is redirected to this page: forbidden.4pu.com; but if we directly type the site url in the address bar of the browser then the site is opening correctly without any trouble.
Please specify whats the actually problem.

Thank you for your sharing this useful topic

Check your .htaccess file and/or plugins blocking access based on HTTP/referer