How can I get my iphone to auto sync with garmin connect app? I have to manually sync every day. I never had this issue with Samsung phone.

At least once a day I'll look at the watch and where the temperature reading is on the screen will just be a dash showing no data.  When I open up the garmin connect app on my phone, there is a dialogue box that says sync your device.  When I had a Samsung phone this never happened.  Is there a setting I can change to automatically sync this or are there compatibility issues with ios that don't exist with android?  Any help is appreciated, thanks.