Nero Express & m3u Playlists

I can’t seem to find the answer so here goes. When creating an mp3 disc I try to add the m3u playlist with the project and get the following error. No compatible file found. Some other posts have said it is possible but can’t seem to get it to work.

I’ve tried adding all the songs in and out of the folder, just adding the m3u. Still no luck. Any help please.