iPhone SE Earpod volume buttons not working on lock screen

[wellingtonius]

Hi, I'm a premium subscriber and since yesterday I've been having the following problem: when I'm listening to music on Spotify with Apple earpods, the volume buttons don't work if my phone is locked. From the lock screen I can see that the ringer volume is affected, but not the music volume. If I unlock the phone, the volume buttons work just fine. This started yesterday when suddenly the volume levels dropped and I wasn't able to raise them using the earpods. Any suggestions? Thanks.