Thanks Johan and Nick, the problem is now solved. Apparently the process of deleting and re-creating an integration API didn’t work out as it should.
I have looked at both problems separately and since my device is functioning correctly, I have performed the following steps:
- Created a new application
- In this new application, re-register the existing devices (which were still linked to the old application).
A number of important keys can be easily copied in this way - Activated my device and checked whether data is visible in the new application.
- Generated an API key for the MQTT integration in the new application.
- Changed the Username and password in node-RED > Securitytab MQTT node.
- Changed in node-RED MQTT node > Properties, the Topic application id and @ttn
- Activated my device and checked the node-RED Debug pane for data
- Payload function copied from old application to new one.
- Registered devices under old application removed
- Removed old application
Everything is working fine now 