Hi, Bobcat, that's not the problem. I can see the files as I always have. I can confirm that the files have content from the shell. I can try to transfer the file (in Coda this is done just by clicking on the file), but at that point the transfer fails.
Good news, though. Restarting the app fixed this problem. I had tried opening connections to non-DH servers (which continued to work) and closing and re-opening the DH server connections (which did not help). But until now I had not quit and restarted the app. That did the trick.