"530 SMTP authentication is required" what does it mean?

This error message is not from your Exchange but from another email server installed on your local system: hMailServer. Don't confuse it with the similar worded "530 5.7.1 Client was not authenticated" message - that one IS from Exchange.

If it is indeed "530 SMTP authentication is required" then POPcon tries to reach your Exchange Server on IP port 25 (SMTP) but instead this other mail server answers with this particular error message. You need to either remove hMailServer from the system and restart Exchange or move one of the two servers to  a different local IP port since both can't coexist on port 25. You can select the IP port that POPcon tries to reach on the EXCHANGE configuration page in the POPcon configuration.