Unable to load my email account onto my Pix3l 3 phone

When I first got the phone, I had my Xfinity email on the phone.  As of a couple weeks ago the Xfinity emails were no updating even though the settings are to update every 2 hours.  I unloaded the Xfinity email and then tried to re-load it, but I keep getting the message that it can not connect to the server.  My Yahoo and Gmail are still working fine on the phone.