RLC-520A - CGI Snapshot returns 404

[user_628934015619111_628934015619111]

I'm trying to get a snapshot from a newly-installed RLC-520A using the CGI guide downloaded from the Reolink website.

The camera returns an empty response with a 404 status code.

According to the guide, the URL should be

http://[ip-address]/cgi-bin/api.cgi?cmd=Snap&channel=1&rs=000000&user=guest&password=[redacted]

I've created the guest user, and can verify the the camera recognizes the user because providing the wrong user and/or password returns

    [
   {
      "cmd" : "Snap",
      "code" : 1,
      "error" : {
         "detail" : "invalid user",
         "rspCode" : -27
      }
   }
]

However, with the correct user and password, the response is a completely empty (0 data length) response with a 404 status code, as confirmed in the browser network console.

So, what is the correct URL syntax to retrieve a snapshot?

[user_628934015619111_628934015619111]

For the benefit of anybody else using that outdated document, the only change required is

channel=0

instead of channel=1