From time to time the local proxy 127.0.0.1 call for Norton to check the email FAILS and POCO returns "Poco encountered a problem while downloading/decoding this message"... on the next or subsequent getmail, the interface works fine and messages are retrieved ok.
Rechecking ALL firewall settings I discovered that POCO was blocked from getting mail from one email account, which was the email account POCO was failing on... after changing the firewall setting to allow POCO access to any email server, all was well again.