I have a a late 2009 21.5 inch iMac with OSX 10.9.5. I am having problems getting my wives Yahoo email account to go "online" with the Mac Mail app. When I added my Yahoo mail account to it, it went online with no problem. I check all the information between the too and I even logged into each account to verify that every setting was the same. Does anyone know of what might be causing the problem or has anyone had this problem?