iTunes can no longer connect to my Airport Express, which is connected to a Bose Wave unit.

Hi, This started about a month ago. iTunes still shows Airport Express as an option in the drop-down, but when I try to connect it searches and searches and doesn't connect. Airport Express is functioning for networking and Internet access purposes. Bose Wave unit is also (independently) working fine. They just don't seem to talk to each other anymore.

What happened? How can I fix this?

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