Flickr Gallery Not Working

Hello, I have several blogs I manage for clients all on the same server. It appears thought the Flickr Gallery plugin is not working on any of the websites. Any ideas on this? I haven’t upgraded wordpress or the plugins. They were working yesterday but seem to be no longer working. I don’t have any error message. Do you this is on Yahoo’s end or the plugin? Could there be a server setting that is conflicting? Any ideas would be great.
Thanks.