Can't skip songs

[Celene]

Hello, so I've been listening to Spotify free for months now with no issues. However the other day I tried skipping a song but I couldn't, a message poppped up saying I'd need to upgrade. Thinking I used up all of my skips for the hour I let it be, however I went back yesterday and then today and still can't skip any songs. And I haven't used the app in days. I have the iPhone 7 and am running the latest iOS version and latest update of the app and I'm not too happy. If anyone knows how to fix this please let me know