Hi Hans,
Could you please try deleting all your devices from both the website and the Android application?
Also, could you please try deleting and redownloading the android application from the Google Play Store?
After doing that, could please try connecting to your device again?
If that still doesn't work, you may have to re-flash the kboot for the KW41Z. To do this, you will need to have a Docking Station so that you can select the KW41Z as the debug MCU.
For instructions on how to re-flash the kboot, could you please check section 4.1.5 of the Rapid IOT Prototyping Tool User's Guide, here?
Could you also try restoring the factory application for the KW41Z, as explained in section 4.1.2?
Please let me know if you still have issues.
Best regards,
Sebastian