Problem solved
On the left of the status screen I changed the selection of the files that need to be taken in considaration
For music : music and images
For films : Videos
For Photos : Images
By limiting the files all problems were solved and I don’t know which (extention) kind of file caused the problem but all the files are now available on the DLNA service
Before I used the dashboard wich was also installed by WD, but this tool was not able to limt the selection
