POPcon downloads email fine but cannot reach my Exchange server

POPcon successfully downloads from your POP3/IMAP server but fails to deliver to Exchange via SMTP. Troubleshooting steps:

1. Verify the Exchange server address — use the server's network name (e.g. exchangeserver), not the internet domain.
2. Verify Exchange services are running — check that "Microsoft Exchange Transport" service is started.
3. Test with PING — run ping exchangeserver from the POPcon machine to confirm network connectivity.
4. Test SMTP port 25 — run telnet exchangeserver 25. You should see an SMTP banner. If not, port 25 is blocked.
5. Check firewall rules — ensure port 25 is open between the POPcon machine and Exchange.
6. Check antivirus / antispam — some endpoint security products intercept or block outbound SMTP. Try disabling temporarily to test.
7. Check the receive connector — verify the POPcon machine's IP address is allowed to connect (see Exchange receive connector settings).