Hello Jan ten Wolde:
It is possible that the Android application record in your NTAG I2C tag is not correct or it was corrupted, so the application cannot be found.
Try restoring the NTAG I2C contents with the Write NDEF option of the Android app. Make sure to enable the checkbox for Add NTAG I2C Demo AAR:

I hope this resolves the issue.
Regards!
Jorge Gonzalez