Join successful but no UnconfirmedDataUp frames – Mixed US915 and AS923 gateways (XYZ property)

Hi Team,

We are facing an issue at our XYZ property (US915 region) where devices are successfully sending Join Requests, and Join Accept is being processed correctly in ChirpStack. However, after activation, we are not seeing any UnconfirmedDataUp or UnconfirmedDataDown frames from the sensors.

Setup Details:

1. Property has gateways supporting US915 and AS923 frequency bands.

2. Necessary region configurations were updated on the gateway side accordingly.

3. In ChirpStack, we are able to see Join Request and Join Accept.

4. No application payload data is received after join.

5. Devices were reset and re-tested, but behavior remains the same.

6. All the US915 supporting gateways and its corresponding sensors work fine.

Additional Context:

We have other properties where AU915 and US915 gateways coexist, and with proper configuration, data is received successfully from sensors without any issue.

For this XYZ property:

1. We applied similar settings, replacing AU915 with AS923 where required.

2. Join procedure works fine.

3. No uplink data after activation.

Questions:

1. Could the coexistence of US915 and AS923 gateways in the same property cause any uplink routing or channel-mask related issue?

2. Are there any specific ChirpStack regional or channel-mask configurations required when mixing US915 and AS923 gateways?

3. Since join works but no data follows, could this indicate a downlink channel-mask or RX window issue?

If any additional logs or configuration details are required, please let me know.

Any guidance would be appreciated.