I don’t know, which loss function you are using, but assume you’ve solved the shape mismatch error.
Could you post the complete stack trace from the new error, as I also don’t know which part of the code raises it.
If this error is raised from the DataLoader, make sure that all images are 3 channel images in the channels-first format. Currently it seems entry0 is still in channels-last and entry9 is a grayscale image without a channel dimension.