Black screen output using Tensorflow's DeepLab

I trained DeepLab on my own dataset with both initialize_last_layer and last_layers contain_logits only both False. I have just 2 classes the background and the label. I tried using --num_classes=2 and3but nothing worked. My ignore_label is 255 while my background is (0,0,0,255) and label is (1,1,1,255). I also gave the label_weights 1:20 but no use. All I see are black images in the segmented_results folder. Any solution?