I did change input size of layers - train is starting but I got:
RuntimeError: CUDA out of memory. Tried to allocate 400.00 MiB (GPU 0; 11.17 GiB total capacity; 10.24 GiB already allocated; 262.81 MiB free; 10.49 GiB reserved in total by PyTorch)
Is it normal that 12 GB of Collab gpu memory is not enough? And even 16 GB memory is not enough!
Ok, I changed input size and batch size and now model is trainable.