09-22-2021 10:11 PM
Could not create SSL/TLS secure channel" exception can occur if the server is returning an HTTP 401 unauthorized response to the HTTP request. You can determine if this is happening by turning on trace-level System.Net logging for your client application, as described in this answer. Upsers
09-26-2021 10:18 PM
I have decided to move the API to my webservice. Working on that now. Simulating an HTTP Post directly from the Desktop to the API endpoint may be the problem. It did work before, but I would not be surprised if it is no longer allowed.