Sena intercom connection problems

I have had my intercom for a while now, and keep having connection problems. I use Samsung mobile phone, ans a TomTom 550 .

The problem is that sometimes when I'm listening to music, when the TomTom gives directions,it either doesn't give anat all, or if it does, the music stops, and doesn't carry on, only way to get the music back is to turn off/on the Sena. I have the Sena app, and have messed about with the settings.

Anybody know how to fix this problem?

Thanks