When I went to the Management tab in ISPConfig and then to Services, POP3 was offline. I checked to see if it was offline by trying to telnet to the server using the 110 port.

In order to get this to work you have to enable it in yast.

In a console type yast this will start yast. Then go to System in yast, then system services. This is where you will enable the courier-pop and courier-pop-ssl services.