I have the latest Avast version installed and my problem just appeared. I Thunderbird for my email and I cannot receive emails from my provider. I just stumbled across Mozilla website about that this may occur and tested. If I turn the MailShield off then it works. I have a Windows 7 machine with a different email account and when the MS is off I can send emails back and forth. The moment I put the MS on my Windows 10 machine up then I get no emails coming or going.
Is there a quick fix for this or try uninstalling and then reinstall? Or try the repair under the add/remove area?