Cisco 7940's are at times unable to access the services or corporate directory menu's. This does not affect all phones at once and so the failure is not on the call manager publisher where these url's 'resolve' to.
DNS is not used as the url's are configured with ip addresses only.
The phones do not use an http proxy to access these url's, they connect directly to the target machine.
This issue can be resolved by resetting the affected phone either by a power cycle or '**#**" reset.