Avast One Paid
After I did the Program update on my Avast One and rebooted, as required, my email would no longer send or receive. I finally realized it may be Avast that is causing it. After turning off the scan incoming and outgoing mail in Email Guardian, it works fine, but will not work when those boxes are checked again.
Win10 Home 64bit
Windows Live Mail (2012)–yes it is an older program but it has worked with my Avast One for years.
Thanks