With the Scheduler window open in the Connector open the Sphere Host Connection via Configuration>Sphere Host Connection. The bottom line should read, Connection to [Your server name] validated (Access: Full). If it says (Access: DNS), then edit your port numbers.
Make sure the following port numbers are open:
- Outbound: TCP port 21 and TCP ports 1025 and above
- Inbound: TCP ports 1025 and above