Symptoms

ABAP agent was installed and also the Machine agent was configured. Machine agent is up and running and a port defined in /DVD/APPD_CUST, field "Machine agent port" (by default 8293) is opened. However, on a status screen (transaction code /DVD/APPD_STATUS) we can see that the Machine agent is not able to connect to the local Machine agent port.

Below errors appear:

Exception in program /DVD/APPD_CL_HTTP_CLIENT======CP, include /DVD/APPD_CL_HTTP_CLIENT======CM004, line 111. 
HTTP response ended with error: HTTP communication failed (code 411: Connect to ******:8293 failed: NIECONN_REFUSED(-10
HTTP response body: <body><div class="content"><div class="valigned"><p class="centerText"><span class="errorTextHeader
404 Connection Refused <br></span></br><span id="msgText">Connect to ******:8293 failed

Transaction /DVD/APPD_CUST

SNP > ABAP agent cannot connect to local Machine agent > image2019-10-23_11-34-40.png

Transaction /DVD/APPD_STATUS

SNP > ABAP agent cannot connect to local Machine agent > image2019-10-23_13-9-35.png

Solution

The recommendation for the customer is to verify these types of connectivity issues:

Make sure to start your Machine agent with HTTP listener parameters.
The 404 error you are getting, indicates that if the Machine agent is running on an SAP application server of an SAP system, then HTTP listener parameters were probably not set. Correct it to resolve the connectivity issue.
Is Datavard Insights license being requested or is it in a trial mode for this monitoring tool?
Check the logs. If no license exists, the Machine agent connectivity error is currently only an irrelevant red icon on the dashboard if Datavard Insights is not used.
Did you start performance collectors to collect metrics (pushed via HTTP SDK) and events (pushed via Machine agent through HTTP listener)?