By any chance you edited a part of code you weren’t suppose to??
any codes or instructions given outside of markers ###START AND END CODE HERE#### aren’t suppose to be edited/deleted/added with any of your written instructions.
Please confirm this as your error is stating you have used Adam optimizer which is wrong optimizer of choice here.
the instruction only explains why the choice of loss was made for sparsecategoricalcrossentropy as we use log_softmax in the GRULM model, you need to add that to loss
actually, after a long review of the code i figured out where the problem was. I set the activation = log_max instead of tf.nn.log_max in the GRULM model. Thanks though.