@ogunal Hi i am facing similar issue, i don’t see any SMTP logs while running Packet capture in Wireshark
Also noticed that Fiddler shows 503 error when the regsvc tries to connect with checkip[.]dyndns[.]org in the example walkthrough it shows 200 code which means it successfully connected
Have you tried checking the simulation mode in Packet Tracer? Sometimes the logs might not show up in real time. Make sure you’re running the simulation properly and that the email is actually being sent. If that doesn’t help, maybe try restarting Packet Tracer or double checking your configurations.