can you provide the JSON of your device? There is probably some attribute missing which might be required with 1017 but which is not added by the cumulocity-ttn-integration.
good question. where to find the JSON? I added last year lots of devices for customers and everything was fine. Now i did the same (add the Node into TTN, it comes up at the device management) but no way to find the LPWAN TAB.
i found the solution:
shomehow the device management application is updated back to the original -->i replaced the application with the version from GITHUB and now its working again.
The UI version now is 1009.0.21
You can use the endpoint described here: Cumulocity - OpenAPI with e.g. Postman to request the device managedObject.
The id of the device can be extracted from the URL when you open the page of the device.