Outlook 2007 Autodiscover pop-ups with Exchange Server 2003

Hi, I have Exchange Server 2003 running on my domain, with about 50 Outlook 2007 clients. One client is receiving an autodiscover pop-up when he opens Outlook, which says that there is a problem with a site's security certificate and that the name on the security certificate is invalid or does not match the name of the site. The domain that it refers to is the company website which there is a link to in the email signature.

Everything that I can find on this subject indicates that the autodicover service was introduced in Exchange 2007, which is not running on my network or domain. I went into IIS on the Exchange Server to look for MSExchangeAutodiscoverAppPool and sure enough it does not exist. None of the other Outlook clients are receiving this error, and many of them have the same domain in their signature.

How can I stop this from occuring, and where might it be coming from? I am considering doing an uninstall and reinstall of Office 2007.
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SteveIT ManagerCommented:
Re-create the user's outlook profile

Also clear his internet cache and delete the cert from control panel, internet options, connection, certificates

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Lacretta IncorvaiaCommented:
Good Morning,

In addition to Sgsm81's suggestion, are you using proxy settings in your browser?  The alert looks like it could be coming from IE.

Take care,
do you have autodiscover.yourdomain.com defined in DNS?

If so remove it, 2003 does not support autodiscover in manner anyway. When outlook finds this DNS entry it tries to use it. But your certificate does not match the domain name and hence the error pops up.
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Lacretta IncorvaiaCommented:
Good Morning Saku,

Just an FYI - this is only happening on 1 of 50 client machines, so is more likely on the client side than server.

well than on that client pc do an ns lookup for that autodisover.yourdomain.com address, it's got to be coming from somewhere. Check the host file there perhaps.
ksoszkaAuthor Commented:
All I had to do was clear temp Internet files and cookies. Nothing else was necessary. Thanks!
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