I have had this problem quite frequently for a while. It seems these apps need a good internet connection to work correctly and at maximum efficiency. It is easier to use a converter https://loader.to and download my favorite music or video in the mp3 version. I paste the link into the converter website, and in seconds, I have the music in the desired file, free to use it anywhere and anytime. Also, I am lucky to avoid millions of ads on Youtube and other platforms that piss me off. After a hard day, I need my music and children by my side.