OutlookAnywhere Proxy Cert Error, Outlook 2007

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Barry St

Exchange 2007 with Outlook 2007 clients. User get an error when opening Outlook when they take their laptops home. It all works fine when they are in the office. Replaced actual domain with " domain" . It used to work and when it stopped working I am not aware of anything being changed.

" There is a problem with the proxy server's security certificate. The name on the security certificate is invalid or does not match the name of the target site mail.domain.com.

Outlook is unable to connect to the proxy server. (Error Code 0)"

It also asks for username and password. I gave it the info at least 12 times and it kept asking.

I put the same Exchange Proxy settings in my laptop with Outlook 2010 and it works. My laptop has never joined their domain.

I ran Exchange Remote Connectivity Analyzer, OutLook Anywhere and it gives me green lights.

They have a cert issued by GoDaddy. The primary name is mail.domain.com and the additional names are autodiscover.domain.com, mail.domain.com, www.mail.domain.com, ex1.domain.local, mail.domain.local, autodiscover.domain.local. ex1 is the name of the exchange server.

When I run a cert test from one of the many websites that test them, it always passes.

Any suggestions would be greatly appreciated.


Hi Barry,
A: 1. Per the infromation, firstly, outlook 2007 works in different ways in internal network and external network. there are many DOC about the difference on the technet library. That means, the OUTlook 2007 worked in the domain network, not infer that it should be work well outside. And I am confused about the " Replaced actual domain with " domain" . " , could you please describle it more clearly. As normal, if your exchange 2007 email system enable the outlook anywhere, and publish all the needed web servcie, and configure proper record on the public DNS server, and issued a properly CERT for the external URL/webservice(must has mail.domain.com, autodiscover.domain.com), and install the root CERT on the client end, and then the outlook 2007 or later version should be work well from external domain, so you could check those to do some troubleshooting firstly.
2. And per the error information, it seems related the CERT issue, check the cert on the proxy healthy, you could follow below to do some troubleshooting.
3. Per the test information, it seems that your configuration all are proper. And work well with outlook 2010. It sounds odd, if so, I would do some test from other different client end, and update the outlook 2007 for the latest version, and make a test through the OWA, and make a test reinstall the outlook 2007.
4. If you want to exactly confirm the issue why occured, the best way to check the log on the outlook 2007 client end, you could post some information refer to it, we could do more reseach regarding to it.
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