Trying to set up a group email "RAM" that will contain multiple email addresses. Receive error messages "check SMTP settings" or "Invalid email address" when I try to send a message to the group.

I am trying to set up the group email "RAM" that will contain multiple email addresses. I have inputted the name "RAM" as a corporation. In the section labeled "Email" I have inputed multiple email addreses so that when I want to send an email to the group "RAM" I just have to input the name "RAM" in the section labeled "To" , input the Subject in the Subject box & the email will be sent to the multiple addresses, yet when I do I receive either one of two error messages being "Invalid Email Address" or "Check SMTP settings" each of which allows me the option of with cancelling the email or send it anyway.