Help please: Suddenly cannot connect RN 426 (Mac)

I turned off my ReadyNAS for a while (to do some voice recording and I didn't want the disk noise). Having turned back on, I cannot connect. The display on the ReadyNAS seems normal, including IP address. It shows up in Radiator on my Mac, and the share protocols (AFP, SMB, unspecified) show up in Finder. But attempts at connection fail.

I have tried turning it off and on again.

Any suggestiions?