You should be able to view all your downloaded  tracks under favourites > Downloaded music when you have no active internet connection.  Does the playlist not load at all? If you quickly test and disconnect your phone’s internet connection, what happens when you launch Deezer and try to load the download tracks?

Hi @Jovss !

Maybe you need download your content via mobile data .

From Deezer page :
Deezer mobile app will only download your music when you are connected to Wi-Fi to save data . 
You can change this to allow downloading to occur when you're using your mobile data. However, it's worth checking with your mobile provider as downloading with your phone's data can result in high charges.

1. Go to Settings 
2. Select Audio 
3. Under Download, select Download via mobile data 

Try to download all your contact using WiFi, that’s quick

and fast. Then clear the cache on the app settings for a fresh start. After they, set your phone on flight mode to test if you are able to play the downloaded content

I have the same issue all my downloaded music doesn’t appear when you open download and then after a few minutes it shows 

frustrating having to wait when it’s already downloaded 

If your downloaded music isn’t loading when you’re offline, ensure the songs are fully downloaded and not just cached for streaming. Check the app’s settings to verify that offline mode is enabled and supported. Confirm there’s enough storage space on your device and that the app has the necessary permissions to access it. If the files seem corrupted, try deleting and re-downloading the music. Additionally, ensure your app is updated to the latest version, as updates often fix bugs. If the issue continues, clearing the app cache or reinstalling the app might resolve the problem.

Thanks it was because the offline wasn’t checked