As I understand it, you have already ensured that the watch is worn correctly on the wrist and that the app is properly installed. If the problem persists, you can try to reset the watch to factory settings (all settings and data will be lost).
Otherwise I would have to ask you to contact Huawei directly, they may have another tip: https://solar.huawei.com/ch...

There is a difference in the strap, your watch has a black strap and the more expensive one has a graphite black aluminium strap.