I am using Avast 8 with Windows Mail. I have AT&T Uverse internet. I don’t have a problem using the listed combo. I did notice a few months ago that the AT&T mail server would hang while checking mail. Usually closing Windows Mail and then trying again would get my email. AT&T is really good at shifting the blame towards someone else when the problem usually lies with them. If you are able to get your mail at times then there is no problem with your settings.
I for one still use Windows Mail because I don’t like web mail. Can’t speak for the OP but that’s just my preference.