The Netvox should have an AppEUI and an AppKey on it’s box - the DevEUI is unique to each device. I don’t need them, but can you confirm that they are present.
Where in the world are you? We’ll need to enter the correct region settings when setting up the device.
Unless you have specific evidence such as time coordination with your node transmission, that may well be from some entirely other TTN or even non-TTN node. It’s expected to see many such messages.
Those don’t appear to match your device settings, so either that isn’t from your node, you are mistaken about the device settings, or the message is misleading…
The -44 RSSI does suggest it is yours though, so I’d try to double check your impression of what the device settings are or should be.
It’s also unclear if you set a matching AppKey between device and network, you will get nowhere until you have
If this message is significant and not spurious, it suggests you have inconsistent choice of regional frequency plan (or for AU915, sub-band) between device, gateway, their respective registrations in TTN and the particular server address the gateway is pointed at.