I can't train a model with mobilbert or Bert in tflite-model-maker

Question

I'm trying to create a neural network for text classification, and according to the script from tensorflow and google, you can use MobilBert for this. First example - tensorflow and Second example - firebase But I get an error:

Node: 'Adam/Cast'
2 root error(s) found.
  (0) UNIMPLEMENTED:  Cast string to float is not supported
     [[{{node Adam/Cast}}]]
  (1) CANCELLED:  Function was cancelled before it was started
0 successful operations.
0 derived errors ignored. [Op:__inference_train_function_164585]

When trying other data sets, everything repeats itself, what’s the problem?