Adding WCF service reference

in .net core we are trying to add wcf service reference and show us TLS SSL issue. Would it be possible that if the end point is requiring credentials?

from connected service > chose wcf to add > add the URI (ends with .svc) > keeping all defaults in next pages, clicking on finish shows below message. there is no other details. 
Final window shows: 
Failed. 
Importing web service metadata.
The request was aborted. Could not create SSL/TLS secure channel. Done.

What I have tried:

re tried couple time, same error