I´ve changed a group´s name but still send emails with old name

I´ve changed a group´s name but still send emails with old name

Hi, I´ve got an email group called "Grupo Macaronesia" associated to an email address
but when I send emails from this addres, the sender´s name is "Fundadores" which is the old name of the group.
I´ve also changed the name in the "send email as" option to Grupo Macaronesia, but still the name that appears is "Fundadores"