Alexa Smart Home "Failed to Retrieve State" - alexa

Question

I am playing with a sample Alexa Smart Home skill - I am not talking to any real hardware or back-end, just trying to get message flow working. I have set up a simple switch/plug/light that can just support turning On/Off - and I have account linked working and the skill enabled. When I try looking at it via the Alexa app on phone or web (with debug enabled) it always says the device isn't responding, or it's "Failed to Retrieve State". I can definitely see the messages in Cloud Watch as follows.
Any idea why I'd be chronically getting such a response??
Request:
"directive": {
"endpoint": {
"cookie": {},
"endpointId": "endpoint-003",
"scope": {
"token": "<<<SUPRESSING>>",
"type": "BearerToken"
}
},
"header": {
"correlationToken": "<<SHORTENED>>",
"messageId": "50397414-bb9d-412f-8a2c-15669978ab64",
"name": "ReportState",
"namespace": "Alexa",
"payloadVersion": "3"
},
"payload": {}
}
}
Response:
{
"context": {
"properties": [
{
"name": "connectivity",
"namespace": "Alexa.EndpointHealth",
"timeOfSample": "2020-06-29T16:49:59.00Z",
"uncertaintyInMilliseconds": 0,
"value": "OK"
},
{
"name": "powerState",
"namespace": "Alexa.PowerController",
"timeOfSample": "2020-06-29T16:49:59.00Z",
"uncertaintyInMilliseconds": 0,
"value": "ON"
}
]
},
"event": {
"endpoint": {
"endpointId": "endpoint-003",
"scope": {
"token": "Alexa-access-token",
"type": "BearerToken"
}
},
"header": {
"correlationToken": "<<SHORTENED>>",
"messageId": "7a8b9a71-adda-41b8-acba-4d3855374845",
"name": "Response",
"namespace": "Alexa",
"payloadVersion": "3"
},
"payload": {}
}
}

Answer 1

Problem was: The "name" in my header response should have been "ReportState". "Response" is only used for things that set/change values.
My general advice is to always verify that THREE things are good:
Initial "Discovery"
"Response" messages
General "ReportState" queries.
By this - I mean that:
Anything you advertised as should be reported in "discovery" better be reported in other ("ReportState") messages. If you advertise a "PowerController" - if your ReportStates don't contain status for that, you'll either not see the status, or it'll keep retrying forever (continuing to look for it) - or you might get some sort of an error.
If you CHANGED your discovery stuff - make sure that you really removed, re-discovered, and that the states (above) for the new additions/removals are okay
Always make sure that "EndpointHealth" is being reported.