I am running Calibre version 3.7.0 on Windows 10. All of a sudden, I am unable to download metadata for a single book. I can open the Edit Metadata window. When I click on “Download Metadata” the only thing that happens is that Calibre freezes and I must use Task Manager to close it. This occurs with all books, including those I had no trouble with before. I have tried rebooting and restarting Calibre and that did not work. My internet connection is fine. Does anyone have any suggestions for what I can try?