StartTLS doesn't work [sending email from C# .NET-library System.Net.Mail]

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1

I try to send an encrypted email using standard C# .NET-library System.Net.Mail.
This library supports only StartTLS mode. I configured my Axigen service according to https://www.axigen.com/documentation/securing-smtp-services-p3277031

But my client cannot connect to the server.
InnerException = {“Unable to read data from the transport connection: net_io_connectionclosed.”}

Log contains the following error:
2020-08-03 11:28:15 +0000 02 e12cb8f0a6ef SERVER:00000000: SSL_connect error (Success)

Has anyone managed to connect to the Axigen from .NET/C#???

PS. I also tried to use an alternative SMTP client for .NET https://www.nuget.org/packages/MailKit/ - it really works.

2

My .net programs had problem for authentication with GSSAPI.
If you are authenticating to smtp maybe you have this problem too.
Disable authentication with GSSAPI and test it again.