Link in HTML e-mail does not work in Hotmail

I send automated mails to hotmail users. (thank you for your registration bla bla) Because plain text doesn't look attractive enough, I use HTML with images. The images reside on a public webserver.

As SMTP server I use the SMTP part of IIS 7.5 (windows 2008 R2). I have an SPF record setup in the DNS. I have also read http://tinisles.blogspot.com/2009/09/sending-dkim-email-from-c.html and found out that sending mail with the SMTP service and a DKIM signature cannot be done properly without an external commercial component. So I do not have such thing (yet).

Now that is all about my background and here is the problem: I have this in my HTML:

<a href="http://www.mydomain.com">click here</a>

But wh开发者_StackOverflow社区en users get am e-mail like that and view it in hotmail. (chrome, IE, safari etc.) and when they hover the link they will see that the url is http://www.mydomain.com but when they click on it. It redirects to:

http://www.mydomain.com/mail/InboxLight.aspx/404.aspx?msg=The%20file%20'/mail/InboxLight.aspx'%20does%20not%20exist

what am I doing wrong? Is it an SMTP/IIS server setting? Did I forget something in my Asp.Net C# code when I have send the mail? Did I forget something in the DNS or HTML markup?

The link works perfectly when I receive the mail in my Outlook 2010 where the domain is also added to the safelist.

EDIT If it seems to be all related to the antispam stuff in hotmail. Should I consider to buy: http://www.youtube.com/watch?v=98oc_5bjjkc

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It could be because the text displayed in the link ("click here") does not tell the user where they are going when they click. Take a look at the hotmail postmaster site for more info, in particular, the troubleshooting page.