Windows 8.1 Pro
Yes. The PC was rebooted.
Thunderbird did not give any error message. When clicking on Get mail, nothing happened. No message stating connection to the mail server. Thunderbird uses port 110.
McAffee Internet Security 2014 installed.
No problems with the network adapter. Any web page accessed OK.
After uninstalling NoMachine, Thunderbird accesses mail servers OK.