Proxy returns "HTTP/1.1 407 Proxy Authentication Required"

Regarding PeopleSoft integration with a 3rd party application hosted over internet.

As my webserver is behind proxy server, I have enabled proxy with out authentication for the 3rd party URL to access.

CURL command , able to connect to the 3rd party .

curl -x  10.221.17.81:8080 https://apm-eur-ww-dev-apim.azure-api.net/

{ "statusCode": 404, "message": "Resource not found" }

But in over peopelsoft integration broker , am facing this error.

From the errorLog.html, java.io.IOException: Unable to tunnel through 51.144.55.103:443.  Proxy returns "HTTP/1.1 407 Proxy Authentication Required"

When I update proxy user name and password in the service operation in connector properties  as Proxy authorization header , the "HTTP/1.1 407 Proxy Authentication Required" is resolved.