3753023 - Error: "503 Service Unavailable" when connecting Data Provisioning Agent to HANA - SAP HANA Smart Data Integration

• DPAgent connectivity is unstable or broken.
• Connecting the DPAgent Configuration Tool to target HANA fails.
• Framework traces contain similar to the following:
  [INFO ]  DPFramework | HttpConnector.fetchToken [] - HTTP Get -> https://<URL>:443/sap/hana/im/dp/proxy/dpproxy.xsjs renewToken=true
  [ERROR]  DPFramework | HttpConnector.fetchToken [] - HTTP/1.0 503 Service Unavailable
                                  Failed to fetch token using URL[https://<URL>:443/sap/hana/im/dp/proxy/dpproxy.xsjs]
                                  Ensure that HANA xsengine is running.
  OR
  [WARN ]  DPFramework | HttpConnector.handleHttpError [] - Request failed. Server response: HTTP/1.0 : 503 : Service Unavailable
                                  Http headers: 
                                  {...}
  [ERROR]  DPFramework | HttpConnector.handleHttpError [] - Server returned: Application Server Error
  [...]
  [WARN ]  DPFramework | HttpConnector.write [] - Http Error::503: Service Unavailable
                                  Http Error::503: Service Unavailable
                                  [...]

SAP HANA smart data integration 2.0

KBA , HAN-DP-SDI , SAP HANA smart data integration (SDI) , Problem