The cache is not at the posted coordinates!
You can learn the coordinates for this mystery cache by completing the "Art in The Glass City" Adventure Lab. You will need a smartphone with data service and the Adventure Lab app installed. You can install the app by going to https://labs.geocaching.com.
You can launch the adventure by opening the Adventure Lab app and browsing to "Art in the Glass City."
Once you've completed the adventure lab, you will have the coordinates to this cache. If you need to retrieve the coords later, you can reopen the adventure in the app, and view the journal entries for each of the 5 locations.
It's not the little free library, but you're close. Smile, you're on camera. The gallery owners have given permission for this placement.