Your script cannot find what is not there. If you load the zoho.com page in a browser and look at the source code, you will notice that the word privacy is not even present. It’s possible that the footer containing the link to the privacy policy is loaded asynchronously, which PHP cannot handle.
EDIT: by asynchronously loaded I mean using something like AJAX, which is client-side only. Since PHP is server-side only, it cannot perform the operations required to load the footer containing the link to the privacy policy.
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