Sidebar Tags Do Not Work

I Created a lot of tags to organize photos that are stored on a separate server. I am able to view the tags in the Sidebar. I have assigned tags to all photos via right-clicking. I am not able to click on the tags in the Sidebar. When I do so, nothing happens. This is in spite of the fact that I clicked "arrange," and then "tags." Essentially, I now have an extensive list of tags in the Sidebar, but there are no photos that I can view via simply clicking on one of the tags. I did not assign any colors to the tags. Could this be the problem?