SBS 2008 - Outlook keeps popping password/certificate boxes

We have an issue where PC users on our domain are repeatedly getting password pop-up boxes or certificate pop-ups when Outlook is open.

If they accept the certificate and/or enter their password Exchange connects to Outlook and works fine, except it happens around 10/15 times per day per user.

I've tried restarting the SBS box while all client PC's were shut down, and also I've tried 'installing' the certificates and removing/replacing the details in the local credentials manager, still can't make any sense of it.

I suspect this is a server problem as it does affect all local PC's, although we have a couple of users who also pickup email on their Android/iPhones which seem to work without issue.

any guidance appreciated!
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Simon Butler (Sembee)ConsultantCommented:
Do you have a trusted certificate, or are you trying to use the built in "free" certificate that SBS installs?
If you have a trusted one, was it installed with the wizards?
If you don't have a trusted certificate, then you should really switch to one, as it will make life a lot easier. You can pick up suitable certificates for less than $80.
I have notes on creating and installing a certificate for SBS 2008 here:


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WORKS2011Austin Tech CompanyCommented:
This is a known issue if you don't have the latest exchange service pack. Please let us know the SP you're running, if it's not the latest perform a full exchange backup and install the latest service pack.
WORKS2011Austin Tech CompanyCommented:
Here's the download link from Microsoft for Exchange SP3
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