Bluetooth spinning looking for new device

Hi, I my iPhone 7 has a problem with Bluetooth, in that it is constantly spinning when I’m trying to link it to a fitness tracker.

The tracker is compatible to my phone.

I have downloaded the fitness app.

I have charged my tracker.

Bluetooth is switched on.

I have powered down my phone and switched it back on - all with no joy!

Has anyone had similar problems?

Thanks