the samsung galaxy watch active 2 doesnt measure stress. the heart rate will show up but the ring that glows around the dial doesn't come up and it says, "Couldn't measure street. please try again". I've tried to reboot the watch but it didn't help. the heart rate measure works though.
I have the same issue on Galaxy Watch. The above solution doesn't work. I think there was an update which caused the issue for me. Hoping Samsung fixes it. Have you found any workaround?