lp/lpr can't print from cups client

["Todd A. Jacobs" <nospam@codegnome.org>]

I have cupsd configured on a remote host to publish its printers, and
the web interface on http://localhost:631 on the local server sees the
remote printers and a defined default printer. However:
    
    $ lpq
    lpq: error - no default destination available.

    $ echo foo | lpr
    lpr: Error - scheduler not responding!

And the following acts as a no-op:

    $ echo foo | lp

This was working as-is a few upgrades ago. How can I troubleshoot this,
and what might be the problem?

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