Hi,
Glad that you solved the issue. Maybe it would be great if you share the error and the fix in case other students face the same issue
Thanks and happy learning

Step 2.D tells you some important things, along with the documentation of tensorflow: tf.math.argmax | TensorFlow Core v2.5.0 tells us there’s an “axis” parameter. there’s also a mention of “axis” in the 2D hints. tf.one_hot | TensorFlow Core v2.5.0 also mentions a depth parameter that could be important for the final shapes

Hope this helps and is vague enough to count as a “hint”

The answer to look at 2D more carefully is for problem 3 - Generating Music, not problem 2 - Building the Model. My answer is for problem 2 - Building the Model.

I got this exact same error but it had to do with my answer for 2C. Within the LSTM_cell function,
I set the initial state to [a0, c0]. However, that will only work for the first value of Tx and never gets updated after that. The variables a and c were initialized to a0 and c0 before the for loop. Once I changed the initial state to the correct variables, it worked.