Hey Vishnu,
I just worked on a related issue with my team where only some users were receiving an empty page after clicking on the email button. Turns out it was a bad character in a quick-message that only they had access to. Most likely the bad character was due to a copy/paste of text added to the quick message. It seemed to have brought over extra curly braces, which threw the HTML off and prevented the page from loading. Just wanted to add my two cents into this since I had a very similar issue.
