Visual Studio workflow not working. System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.

I'm glad to hear you found a workaround for the issue, if you have any other issue about SharePoint, you are welcome to raise a ticket in this forum.

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[Visual Studio workflow not working. System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.]

Issue Symptom:

OP created a workflow in the Visual Studio 2019 for SharePoint 2016. When the workflow starts it is showing following error:

HTTP to: https://myspserver/sites/site1/_api/sp.utilities.utility.ResolvePrincipalInCurrentContext?input='i%3A0%23.w%7Ccontoso%5CSPFarm'&scopes='15'&sources='15'&inputIsEmailOnly='false'&addToUserInfoList='false'&matchUserInfoList='true' System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult) at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)

This is dev environment, and the SSL error because certificate in browser has expired. But if OP create SPD 2010 and SPD 2013 then they work just fine.

How to make this Visual Studio work with SSL error? Some way to ignore error?

Current status:

OP generated self-signed certificate and issue is now fixed.

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