How big are Cifar10 images? I think they’re only 32x32, right? It’s possible that you are using a deep network that is “too deep” for these images, because it is trying to do too much pooling / down-sampling.
Given the error you saw, I would double check that (1) Your input tensors really are BCHW and (2) Your input tensors have enough height and width to survive through all the downsampling in your network