@Ernst-Jan15 Try latest update of the app. ( version 0.3.0 ) The issue is related to an update on whatsapp side, not the update to 24.04, it's a coincidence. But latest update in openstore should solve the problem and more. It also includes notifications, if you disable background suspend and keep the app open in background.

Most accounts nowadays force users to use app passwords when using 3rd party apps. Most likely this is what you need.