Digits multi-class classification HGO & SVM

Error message

At the very end of the this sample code I get an error message at the line 100 :

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

Error in Luca3 (line 100)

trainingFeatures(i, :) = extractHOGFeatures(img,'CellSize',cellSize);

I do not know how to make it work. Somone could maybe help me find a solution ?

I'm simply copying the code from the matlab documentation following :

https://ch.mathworks.com/help/vision/ug/digit-classification-using-hog-features.html