iOS 9.3, chromecast audio: random dropouts

[brki]

Plan: Premium Family

Country: Switzerland

Device: iPhone 4s

Operating System: iOS 9.3

My Question or Issue

When casting, the audio cuts out (e.g. no sound from the stereo) several times in 5 minutes.  After 5 minutes I find another solution for my music fix.

This doesn’t happen on an iPhone 6s with iOS 11.4.

I saw in another thread that this problem was fixed in a recent update to the Spotify app.  The app version we’re using is the same on both phones: 8.4.53.

I’ve tried the usual things like restarting the phone and even reinstalling the app; nothing has helped.