Hey! Thanks for coming to the community for help :)
Luckily, your iPhone recognizes the premium, meaning this likely isn't an issue with the actual subscription. First, I'd make sure you're signed into the same account on all 3 devices. It may sound simple, but it's often overlooked!
If that isn't the issue, performing a clean reinstall of the Spotify app should do the trick.
Hopefully this helps! (and if it does, marking this as a "solution" will make it easier for others with the same problem to find)