Either way, I see that you are using some kind of mask as input.
Can you check what’s the dimension of the data from dataloader?
I suspect that the number of channels in the mask data is 19.



 oguzeraysal:

            nn.Conv2d(1, 64, kernel_size=3, stride=2, padding=1),



In the first conv layer, the input channels expected is 1, as given in error message.