The problem:
2 hours trying to send an e-mail message from my ASP.NET contact form (this time in .NET 4), and the only exception I am having is SMTP authentication required.
Reading 30 more minutes the hmailservers' forum and the tones of different configurations. Non of them works I am keep getting SMTP authentication required message...
The funny things is that I am reusing my code written in ASP.NET 2 for sending e-mail for years without any problem on different server. I am completly confused, where is the problem the hmailserver configuration or code error, who knows... and suddenly google helps again with this mySmtpClient.EnableSsl = False so simple isn't it?!
Looks like in ASP.NET 4 they changed the SMTP SSL to TRUE by default hmm.
Hope it helps.