Unable to set up Godaddy account in mail

Cannot get my godaddy email account set up on Mail. Error message "Internet accounts could not log in to Exchange server...". Spent hours with Godaddy helpline that cannot find any problems on their side. As a matter of fact it works fine on my iPhone. They say it is an Apple problem. Password is current. Following all the steps. Mail program keeps asking me to enter the password. This is bizarre as it used to work at the beginning and now it does not anymore. What to do?