Moved to Business > Web Gateway for better response.
We'd need a little more information to help identify the problem.
Do you know what rule is causing the block? If so, can you share that portion of your rules with us?
I am not sure I can, as this is a client of mine. But I just noticed there are "Rules" that are IP based (not domain based). I think that is the direction for research. Can you point me to online documentation about the Rules, and how Web Gateway processes thru the 'cycles'.
You're right...The IP rules are probably the problem.
There's a great collection of documents here: McAfee Web Gateway Best Practices and Common Scenarios
I'd suggest that as a good place to start and then come back here if you have specific questions.