Exchange 2010 Out of Office message states Server not available.

right-click the Outlook icon in the System Tray and select Test E-mail AutoConfiguration
does it run / pass on everything ?

Also use the Get-ClientAccessServer | fl Name,AutodiscoverServiceInternalUri command. That will show you the current autodiscover uri's for all of your servers.

Now to configure your Autodiscover Service correctly use Set-ClientAccessServer -Identity  -AutoDiscoverServiceInternalUri “https:///autodiscover/autodiscover.xml”. Now one last step, you will need to set the web services directory to point to the correct interal and external URLs. Do that using Get-WebServicesVirtualDirectory set-WebservicesVirtualDirectory -intrnalurl https:///EWS/Exchange.asmx -externalurl https:///EWS/Exchange.asmx.

It will also be necessary to update your security certificates on the internal machines (and possibly generate a new security certificate depending on your configuration) to avoid getting a security error. But you should now be free to alter your OOF settings from Outlook 2007 with no further error messages

refer this

http://www.proexchange.be/blogs/exchange2007/archive/2009/07/14/your-out-of-office-settings-cannot-be-displayed-because-the-server-is-currently-unavailable-try-again-later.aspx

take a look at this article
https://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_3585-Exchange-Autodiscover-Service-OOF-and-OAB.html

I am running Windowws 7 desktops, I do not have an option to select test OOF.  I get no context menu when I right click on my outlook icon....even if I hold CTRl.  Is there another way to get to it?

right-ctrl+right-click

autoconfiguration was unable to determine your settings.

read the article i posted earlier that describes autodiscover