Hi @AnjaliM
Not sure why that would be happening… could it be a check to see if the domain name has been registered? That would be an easy check and good for blocking that type of spam. If (and, that’s if) HubSpot is checking domain validity I wouldn’t turn it off even if I could.
We typically use Mailinator (email equivalent of a burner phone) for testing forms - you get the benefit of a valid email address and you can check the replies.
Have fun
Mike