Error after merging two Deep Learning models VGG16 and ResNet50
The 2D feature map is extended to the output layer and hence throwing errors at the Softmax Layer.
 Add Flatten Or GlobalAveragePool after Concatenate.
mergedOutput = keras.layers.Concatenate()([vgg.output, resnet.output])

mergedOutput = keras.layers.GlobalAveragePooling2D()(mergedOutput)  # This line

x = keras.layers.Dense(256, activation=&quot;relu&quot;)(mergedOutput)