Chromecast: App is connected but does not play music

[1135846425]

Plan

Premium

Country

Germany

Device

iPhone SE

Operating System

iOS 12.3.1

My Question or Issue

Hey spotify. I use my Chromecast to stream to my TV and although the app is connected and showing the right song, no audio is coming out. I can see the timer moving in my phone but not on the TV screen. 

I have tried resetting Chromecast, the app and even my phone. Nothing works. Any other app is working perfectly with Chromecast. 

Hope you can help me! It was working perfectly last night!