Run inference with Tensorflow lite and Android. Error: Output tensor at index 0 is expected to have 3 dimensions, found 2

I'am currently working on a custom Objekt Detection Model. At the momemt i try to run the model on Android.

To create a TFLite model i followed this Google Codlab

https://colab.research.google.com/github/tensorflow/models/blob/master/research/object_detection/colab_tutorials/convert_odt_model_to_TFLite.ipynb

It works without any errors and i can download the model.

For testing i use the sample app from Github.

https://github.com/googlecodelabs/odml-pathways/tree/main/object-detection/codelab2/android/final

I put my model into the asset folder and changed the model path to point at my own Model.

If i try to run the inference i get the following error.

java.lang.AssertionError: Error occurred when initializing ObjectDetector: Output tensor at index 0 is expected to have 3 dimensions, found 2.

I dont know whats is going wrong, does anyone know how to fix this ?