Connect Spotify to receiver via app IPhone

[MarinusvdEnde]

Plan

Free/Premium

Country

Netherlands

Device

(iPhone 6s)

Operating System

(iOS 10)

My Question or Issue

I live with my girlfriend and we both have an IPhone 6s through which we can play music via the Spotify app on our receiver. So we open the app, find a song, and press connect with the receiver in the app. The phone in this way works as a remote control.

Since my girlfriend started using here IPhone to listen to music from Spotify by the receiver my IPhone is not able to see of recognise the receiver anymore. It is only possible to see the receiver and connect to it by here phone. 

Is there any way it can work on both our phone´s? I tried reinstaling the app and shutting down the receiver a milion times and it drives me crazy.

See the immages below of both pur phones.

Thanks!