It's a pop-up you may have seen before when using Microsoft Office Outlook 2007 to open a mailbox homed on an Exchange 2007 Mailbox server in your Exchange organization...

When opening a mailbox homed on an Exchange 2007 Mailbox server, Microsoft Office Outlook 2007 will use services provided by a Microsoft Exchange 2007 Client Access server in order to configure its Out-of-Office settings. If you get the error above, there are a couple of things that might cause this error...let's have a look :-)

1. Check if you are connected using RPC of using RPC over HTTP

To check if you are connected using RPC or using HTTPS, you can right-click the Outlook icon located in your system tray, and select Connection Status.

I'm connected here using TCP/IP, and not using HTTPs.

2. Check which URL your Outlook is using to configure the OOF, and if you can browse to it!

When you press Ctrl and right-click on the Outlook icon located in your system tray, you can select Test E-mail AutoConfiguration.

When you select this, enter the e-mailaddress of the mailbox you have opened, and the password. Since we are not using Pop or Imap, no use in leaving the GuessSmart checkboxes checked.

After clicking Test, you will get the URL used to configure OOF, as shown below.

And it's the URL next to OOF URL, that is of interest to us. Since you checked how you were connected in step 1, you need to focus on the URL defined with Protocol Exchange HTTP, or on protocol Exchange RPC if the connection status revealed TCP/IP, which it did in my case.

When using a browser, you should be able to enter the URL, give your credentials, and you should end up with something like this:

 If not, check:

- the URL, is it the correct one? In the example below, a URL is returned by the Autodiscover service which is completely incorrect!

 To change the URL, you need to use the Exchange Management Shell cmdlet Set-WebServicesVirtualDirectory on the Client Access server which provisionned the incorrect information. You can use the same Test Autoconfiguration to retrieve the CAS responsible for the wrong data.

And on that Client Access server (nts00), I change the internalURL and the externalURL to match the correct settings!

- make sure the ExternalUrl is accessible from the outside (and published!)

- check permissions set on the virtual directory EWS, they should match the ones below

3. Make sure you have a valid certificate

Make sure you have a certificate configured for your Client Access IIS service, with the correct names, issued by a trusted CA for your clients, and that is valid for the current time! In the example below, my certificate enabled for IIS is valid, issued by a trusted CA, and has the correct names!

4. Check Outlook Version if logged in using a different account

When using Microsoft Office Outlook 2007, there was a bug which has been solved in Office 2007 Service Pack 2.

Situation: you log into machine x, using the account Administrator. You configure Outlook to open the mailbox of user Ilse Van Criekinge, and you log into the mailbox by providing Outlook with the credentials of user Ilse Van Criekinge. URLs returned by Autodiscover are correct, reachable, certificate is ok, but still you get that error box listed in the top. The reason is that Outlook up until Sp2, will query the Exchange Web services using the credentials of the logged in user, in our example user Administrator.

You can see this information when checking the log files on your Client Access server.

 Applying Service Pack 2 of Office 2007 resolves this issue :-)

And OOF can be set, even when logged in to the machine with a different domain user :-)

OOF can be scheduled :-) 

-Ilse