Over the past few days I've been running into problems with Thunderbird connecting to one of the 3 AOL mail accounts I use. After discussing this with Thunderbird's support staff I attempted using TB with Avast totally disabled (all shields off) and the issue cleared up and so far has yet to re-occur. However, I do not trust this to remain so as I had been able to fix this issue before without having to disable Avast at all. The issue came back once I had shut down my PC and then turned it back on the next day. Before anyone asks, yes I DO have TB allowed under exceptions and no I DO NOT have Mail Shield.
My stats are:
OS -- Windows 10 Creators Update 1803
TB -- vers. 52 (Updating to latest TB DID NOT solve this issue)
Avast Free -- version 19.2.23.64 (build 19.1.4142.454)
Virus Definition version - 190212-4
UI version: 1.0.326