Training a Variational Autoencoder on sine waves

Hi,

I am trying to train a variational autoencoder on sine waves using the code from https://se.mathworks.com/help/deeplearning/examples/train-a-variational-autoencoder-vae-to-generate-images.html

The code seems to be running. However, the ELBO loss is identical through all the epochs. Therefore, it seems that something is wrong with the training part. When I run the code with the data given on the webpage, I get the same results as on the webpage (the training part works, ELBO loss is reduced through the epochs). I attach two m-files. ConvAE.m is the main code and Sinus.m is the sine wave data set. I have not attached the other helper functions as they are identical to the ones on the webpage. Some parameters in ConvAE.m have been adjusted to match the data set that I use.

Can anyone spot the problem?