AU915 gateway receives Join Requests but no Join Accept is sent

Hello ChirpStack Support,

I am contacting you because I am facing an issue with an AU915 setup in which the gateway is receiving OTAA Join Requests, but no Join Accept is being sent back by the network.

Current setup:

• Gateway: Dragino DLOS8N-EC25 AU915
• End node: configured to AU915
• Region / frequency plan: AU915
• Gateway sub-band: FSB2
• Network environment: gateway connected to ChirpStack
• These tests are being performed in Europe, outside the usual deployment region for AU915

Observed behavior:

• The gateway is online and receiving uplink traffic
• In the gateway traffic/logs, I can see repeated OTAA Join Requests from the end node
• However, no Join Accept appears to be generated or transmitted back
• On the ChirpStack side, there are no events appearing in the device event tabs during these join attempts

What has already been checked:

• The gateway frequency plan and sub-band were reviewed and corrected to match the end-node traffic
• The end node is also configured to AU915
• The issue persists even after correcting the sub-band
• The main symptom remains the same: gateway receives Join Requests, but the join process does not continue on the ChirpStack side

I would appreciate your help verifying:

1. Whether the gateway uplinks are correctly reaching ChirpStack
2. Whether ChirpStack is processing the Join Requests
3. Whether there is any issue with the gateway-to-ChirpStack forwarding path
4. Whether there is any gateway region / backend / MQTT topic configuration issue that could prevent the Join Request from being handled properly

Best regards,
Simão