As has been said, Strava took away functionality so you have to record on your phone via a third party app and sync to Strava.
I had a world of trouble with this using Tickr HRM, S9 and the Wahoo app. It would record may bother until the screen was locked, then stopped recording. I knew it was a permission issue somewhere but took ages to fix. Basically you have to have location set to on at all times, not just when app is in use. I queried this with Wahoo and they said, oh, sorry, we’ll fix that at some point, keep checking the app store!
However, now the settings are all correct, it records a treat and uploads straight away.