Android UMP - Request consent always fails

I implemented consent request using UMP according to this guide.

I use real device to check the implementation:

    fun initialize(activity: Activity) {
        val params = ConsentRequestParameters.Builder()

        if (BuildConfig.DEBUG) {
            val debugSettings = ConsentDebugSettings.Builder(context)
                .setDebugGeography(ConsentDebugSettings.DebugGeography.DEBUG_GEOGRAPHY_EEA)
                .addTestDeviceHashedId("E608A703339C5546343D0D3A2AC00FB0")
                .build()
            params.setConsentDebugSettings(debugSettings)
        }

        consentInformation.requestConsentInfoUpdate(
                activity,
                params.build(),
                {
                    // Proceed with result
                },
                { log.debug("error during consent request $it") }
        )
    }

Each time this results in error: W/UserMessagingPlatform: Invalid response from server: Failed to read publisher's account configuration; try again later.

Things I've already checked:

• App ID (from AdManager) in Manifest is correct.
• There are no additional parameters in request, everything as described in guide.
• Referred to this answer, we have Funding Choices account. And right now it is in transition, as mentioned here.
• Account is active and not under verification.

Any ideas why it fails?

The message, specific to app and regulation zone was missing. Inside ad managing service (AdManager, AdMob, etc), in Privacy & messaging section. There should be specific message added for zone (e.g. GDPR). It is required step to make UMP work.