2nd issue is likely to be a firewall issue. Try a telnet connection to the pop3 server from the server where MW is hosted. http://kewl.lu/articles/pop3/
If you can't establish a connection then you will need to look at your firewall settings. Not knowing what you are using makes it impossible to say what you need to do. You might find a previous topic helpful, it is about SMTP but the principles are the same. https://forum.mailwizz.com/threads/delivery-server-error.300/