Cannot send or receive mail from my xxx@zoho.com user id

Cannot send or receive mail from my xxx@zoho.com user id

I have added several email accounts (comcast, gmail) to zoho and can send and receive mail from each of them.  However I cannot send or receive mail from my cr1127@zoho.com user id.  That user id ( cr1127@zoho.com) also does not show up in the "Send Mail As" section.  I've tried looking through the FAQ's and Forums, but can't seem to find an answer.  Might anyone have any ideas?  Thanks ... Chuck