I have faced this error on my CNN: (Layer 5 is expected to have a different size)

I'm trying to implement the CNN algorithm that used on paper (A Deep-Network Solution Towards Model-less Obstacle Avoidance)for Lei Tai, Shaohua Li, and Ming Liu; and when I put their specification of CNN layers; I got the following error: using nnet.cnn.layer.Layer>iInferSize (line 266) Layer 5 is expected to have a different size. if anyone has an idea what is going on, which size they mean? and why I got this error? plese, let me Know.     layers = [imageInputLayer([120 160 1],'Normalization','none'); convolution2dLayer(5,32,'NumChannels',1); reluLayer(); maxPooling2dLayer(2,'Stride',2); convolution2dLayer(5,32,'NumChannels',1); reluLayer(); maxPooling2dLayer(2,'Stride',2); convolution2dLayer(5,64) reluLayer(); maxPooling2dLayer(2,'Stride',2); fullyConnectedLayer(5); softmaxLayer classificationLayer()];