If you have a self signed certificate on your server, continue reading:)
The problem is that the certificate is not installed on the client; navigate to https://your-server and install the certificate.
To make this work, your OAB URL should use a secure connection to your exchange server. To see this, hold ctrl down and right click on the outlook icon next to the watch (on a client). Press test connection, and fill in your password. Look for OAB URL and ensure that it starts with https. If not, go to your exchange server, Exchange Management Console, Server Configuration, Client Access, Offline Address Book Distribution, Right click on OAB, select properties, URLs; replace http with https, so it looks like https://server.domain.dk/OAB.
Wait until the setting is replicated to the outlook clients (restart outlook), and run the test tool again. Now everything should be running.
NB: If you have a Vista client, you have to run internet explorer as administrator to install the certificate. Do this by starting a terminal and type “runas /user:administrator iexplorer”. When installing the certificate, you have to choose the “Place all certificates in the following store”, and then “Trusted Root Certification Authorities”. Good luck…
