ERR_UNSUPPORTED_PROTOCOL for client in helia-lan-discovery

[macterra]

using Node.js v20.11.1

npm run client fails with this error:

file:///home/david/self/helia-examples/node_modules/@libp2p/multistream-select/dist/src/select.js:95
    throw new CodeError('protocol selection failed', 'ERR_UNSUPPORTED_PROTOCOL');
          ^

CodeError: protocol selection failed
    at Module.select (file:///home/david/self/helia-examples/node_modules/@libp2p/multistream-select/dist/src/select.js:95:11)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async ConnectionImpl.newStream [as _newStream] (file:///home/david/self/helia-examples/node_modules/libp2p/dist/src/upgrader.js:330:50)
    at async ConnectionImpl.newStream (file:///home/david/self/helia-examples/node_modules/libp2p/dist/src/connection/index.js:94:24) {
  code: 'ERR_UNSUPPORTED_PROTOCOL',
  props: {}
}

I'm running npm run server in another terminal on the same machine.