Is there any restriction regarding your sample code ?

Question

I modified your sample ,MailSendWinForm_VB', in Visual-Studio 2010 debugging-mode everything works fine, but the compiled Version gets a socket error 10013 (Access denied).

Answer 1

There is no such kind of restriction.

Can you please create communication logs for the two cases and send the log files to support@rebex.net for analysis (or post it here).

It should show the differences between the two cases.

The log file can be created like this (in MailForm.vb constructor):

_smtp = New Smtp
_smtp.LogWriter = New FileLogWriter("c:\data\smtp.log.txt", LogLevel.Debug)