AFP was working fine, after trying to start SMB, is now inaccessible

I had AFP working very nicely on 10.3.5 server with both LAN and WAN 10.3.5 clients. Then I (unsuccessfully) tried to get SMB up and running, and ever since that failed attempt, AFP cannot now be accessed, not even on the LAN. When I try to access the server through the ‘Network’ volume list in the Finder window, I can see the server name, but clicking on the Connect button just pops up a dialog box with “The alias cannot be opened, because the original item cannot be found”. Via Command-K, I get something different – “could not connect to the server because the name or password is not correct”.

What have I done? One thing you should know is that I tried setting up SMB as Kerberos, switched to Standard, then back to K – Apple’s online docs suggest this can cause a problem.