问题
In VS2019, when I attempt to add a web reference to a wsdl provided by an API ([url]/file.wsdl - which is different from what I'm used to, that being [url]/?wsdl) I can see the wsdl itself (after selecting the appropriate cert), but I get this error in the area where it shows the "Web services found at this URL":
There was an error downloading '[url]/file.wsdl/$metadata'. The request was aborted: Could not create SSL/TLS secure channel.
I can navigate in a browser to both the wsdl file AND the metadata url (although that metadata url shows me just "SOAP-ENV:Server"). So I am reasonably sure it's not a certificate issue (which we certainly did have, but seem to have since been resolved). I've never seen this one before. All questions related to this topic here seem to be cert related or, in the case of $metadata request failures, a different error (404 for example).
来源：https://stackoverflow.com/questions/57824425/error-adding-web-reference-when-attempting-to-download-url-metadata