Cannot send email zoho crm

I cannot send invoices via Zoho CRM I get a gmail server error.
Where is this set up? I cannot find it in CRM or Zoho Accounts.

Also Zoho Accounts will not allow me to add Info@boxoutbullying.com
I get the error of the address already exists, However it is not in the list, I NEED to set this as the Primary address.

Help.
Thanks