I had a similar error in a code that worked in 2023 and does not work anymore in 2024. The problem was solved by replacing : encoded_model = Model(inputs=NN_model.input,outputs=NN_model.layers[0].output) by encoded_model = Model(inputs=NN_model.layers[0].input,outputs=NN_model.layers[0].output) or by encoded_model = Model(inputs=NN_model.inputs,outputs=NN_model.layers[0].output) I hope this helps solving your problem.