File "/home/simon/anaconda3/envs/ldm/lib/python3.8/site-packages/torch/nn/modules/conv.py", line 443, in _conv_forward
    return F.conv2d(input, weight, bias, self.stride,
RuntimeError: Given groups=1, weight of size [192, 3, 3, 3], expected input[6, 4, 64, 64] to have 3 channels, but got 4 channels instead
Probably a batch size extra dimension?
          
happens same to me with the recent v.1.4 model and command:
python scripts/txt2img.py --prompt "a photograph of an astronaut riding a horse" --plms
        size mismatch for first_stage_model.post_quant_conv.bias: copying a param with shape torch.Size([3]) from checkpoint, the shape in current model is torch.Size([4]).