Android Auto

[Old Dear]

Hi, I'm after some advice please, we've got a 72 plate Corsa.   

We've successfully paired a Xiaomi Redmi note mobile phone  [my phone]to the infotainment centre. It works fine for calls, msgs etc and for the maps display.

However, when my other half tried to pair his mobile (same as mine by the way) he can't get it to work. We've checked everything obvious. Any ideas please?

Any answers need to be 'non-techy' please as I'm a bit dim and old, lol