Question on my zoho email account

Question on my zoho email account

My email for my URL (handevents.com) was set up as carl@handevents.com. I have tried sending emails to that zoho email account but it doesn't go through. If I use carlhand@zoho.com I can send and receive emails. Why can't I use the original name of carl@handevents.com instead of carlhand@zoho.com?