Problem exporting playlists

When I export playlists to an external device, the songs are exported and appear in the collection, but the playlists that are in the software don’t appear!! I’ve already tried dragging the playlist to the device and through the sync manager, the result is the same!!! I’ve tried on several devices, this started with a device (pen drive) that I used regularly and already had the library exported, one day the playlists stopped appearing!!!