Honestly this what i do every time and it works perfectly. The best will be to check that both the datasource and the agent are not using encryption as from what i see that is disable on the ESM datasource but what about the agent.
Another thing you can try so you could see whether the logs are arriving :
tcpdump host "yourhostip" and port 8081
Another thing you can check is the agent log:
C:\Program Files (x86)\McAfee\Windows Event Collector\debug.log