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Check your folder permissions on upload folder or check your upload size maybe it's too small.
Path for upload folder?
After installation in /PF.Base/ the folder "upload" there is not
Is normally? Little bug? I need to create manually?
If yes permission to set is 777 recursive?
I think I know why everything works well with Music app on one domain and not on the other domain. The working one was a new installation of the latest phpFox, the other one was an upgrade from version 4.5.3. There was no update on the Music app, so the old functions remained.