I'm trying to enable the Blood Oxygen app on my iWatch (Series 7)

I'm trying to enable the Blood Oxygen app on my iWatch (Series 7). I getting the error message, "Unable to confirm your location. Make sure your iPhone is not in airplane mode and has a working SIM card to proceed."

I have a working SIM card and have followed the instructions to make sure my location is enabled.

I don't know what else to do at this point. Any help is appreciated.

Thanks,

Julie