This seems to be a re-occuring issue (when searhing the error message). The Content Viewer services were down, which caused this error. The bigger issue here is that you couldn't even view details of a file (which is the default click behavior). Viewing details failed with the same error message, which only caused confusion, as previewing wasn't even attempted.
Please separate the "View Details" functionality from the "Content (Pre-)viewing" functionality, so people are still able to "work normally" even though the Content Viewer services are down.