Because you cannot access edit page without __nonce and post_id
This will be fixed.
Exclude grid.less from main.less and compile it.
Try this : “user:rahularyan your search string”
There is a simple solution for that: Disable button after it’s been pressed, Enable it only after ajax returned “failed”. Let the users click disabled button all they want. Showing error messages is so previous century.
Why you want to do so? if user want to add email then simply show register popup..? Showing register popup will be better then adding field for email.