Inspire HR not recording heart rate when I run

[Greenbeck]

When I run with my fitbit HR, no heart rate data is provided when I complete my run.

I always record my run through the fitbit app and ensure my fitbit is connected to the phone before I commence the exercise.

When I finish the run it says there is insufficient HR data for that exercise period (against the map of my route, peak zones, etc.), however, the HR tracker section in the app shows that my heart rate was indeed captured during that time.

Why does the HR element of the exercise feature not work? I bought this watch specifically to track my heart rate whilst running.

[Jrdubyakc]

@Greenbeck Try moving it up a bit on your wrist (three fingers up from your wrist bone) and perhaps a notch tighter. 

[Greenbeck]

I have tried placing it in a variety of locations and tightened it in different ways but nothing seems to work. As I say, the device is registering a heartbeat as the heart rate monitor in the app detects my heart-rate during the period I run, however, it doesn't overlay the data in the exercise section.