Made a deinstallation, reboot, clean install, reboot. Result: Same story as before. Same error message within OL2013. Stopp AVAST and OL works again as expected.
What I don't understand is the fact, that OL was working fine till approx. noon today and is failing to download whilst AVAST is activated thereafter. . . .
Any more ideas?
PS: I have a similar trouble on another system where I use "tunnel" to pass email's from an app to gmail. As long as AVAST is active, no msg's will leave. Without AVAST, everything works fine!