Alexa Devices never discover Hue

I've tried with an Echo Spot, Echo Dot 3rd and Echo Dot 2nd Generation. All on the same wifi network but they never find any Hue-Bridge devices in Discovery mode nor even show up in the logs when prompted via voice or the Alexa app. What am I doing wrong?

Is your port 1900 free - try the check in this post: Alexa-Hue Bridge Debug Logs + Port 1900 Check

The Echo Dot 2nd Gen should work OK.

Thanks for the help! Not sure- this is the response to that query:

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
IndigoPlu 464 noahkadner 12u IPv4 0x16249e4cc17216cf 0t0 UDP *:ssdp

And a recent plugin log:

Finally got it working by forcing the plugin to use Port 1900 instead of 8178.

Oops I spoke too soon- now it doesn't see anything again. No appearances in the log and the Echo reports devices aren't responding.

Port 1900 is used for discovery and shouldn't be used by your Indigo Alexa-Hue Bridge device - it should be something like 8179 onwards.

When you ran the lsof command it showed something was using 1900 - most likely the Alexa-Hue Bridge plugin?

You can check this by using the pid number (464 in the output previously posted), use the Activity monitor to display the CPU, click on the pid column header to sort by pid number, highlight the process line that contains the pid and then press the i (info) button to display info about the process. Click on the Open Files and Ports tab and look at the first line which should contain some info that will indicate what the process is (if an Indigo plugin)

Seems to be happy again on 8179.