Our smarthome device works fine when using voice control. You can even query the state and other parameters using voice commands (alexa queries with a reportState). However when you select the device from within the Alexa App, the App says that the server is unresponsive and shows a message saying: "Waiting for <our company name>". I can see that every time you select a device from within the App, Alexa sends a reportState query to our servers and we respond the same way we do for voice activated reportStates.
We don't have "proactively report state" enabled, just the "retrievable" option is enabled.
How can we fix this? Users thing that Alexa or our device isn't working correctly when they see the Alexa App show this message.