As a quick thought… are you carrying the mobile on the treadmill, or using the Apple Watch to try and convert the treadmill exercise? I apologise if you have already answered this elsewhere, A few people have mentioned that they have tried recording indoor workouts with the watch but had minimal or zero conversion when using the watch on it’s own indoors. At present, the Watch App uses the old outdoor only algorithm for verification and conversion. Even when using the iPhone 7 as the parent mobile, any steps submitted from the watch when in doors will most likely not be verified. However, if you wear the iPhone 7 on the treadmill, you should have any luck start to see some conversions.
I myself use an iPhone 7 Plus as the parent device and I alternate between the Apple Watch three and Apple Watch for you to battery life issues.
As an example, for some unknown reason yesterday I ended up going for a bit of a long stretch and ended up finishing of the day with 20k steps on the treadmill. Out of a total of 120,000 steps, I only lost 12,000 in conversion and Majority of these not verified were outdoor steps.
Please consider that I do not work for Sweatcoin, I need opinions and ideas are based on my own personal experiences and may not reflect the opinions of others.
I hope this info helps even a little