Photos not displaying in Flickr module

I'm trying to use Flickr (the module), but am missing a step somewhere. I'm only getting the "This photo is currently unavailable" graphic from Flickr. I did get the photos for a few minutes, but not now. Also, if you click on one of the graphics, you're taken to the correct photo on Flickr. These are the steps I've taken:

I've configured the settings with my Flickr API key, secret and username. I added the Flickr filter on the input format I'm using on the page. I configured permissions to allow anonymous users access to view all photos. On the Flickr side, my photos are public and I double-checked the photo IDs.

Does anyone have suggestion for what I'm not doing correctly?