Music from iTunes won't transfer to my iPhone

Hi guys, normally when I download free music from the internet (its free music, I'm not downloadingillegally) I am able to download it into my iTunes and then I am able to put those songs on my iPhone with no problem. Now the situation I currently have is that when I try to transfer a song, album, playlist, etc it doesn't allow me to. I usually drag the song into my iPhone tab on iTunes but now it doesn't let me. Usually it lets me drag into it but now it doesn't. I recently signed up for Apple Music and I am wondering if thats the issue. Can someone help or explain what I can do? Is it because I have Apple Music?

Any answers/help are appreciated 🙂