If your Xiaomi Smart Band 9 Pro is not reconnecting to your phone, try the following steps:
1. Try removing the Mi Fitness APP, reopen it, and check for successful reconnection;
2. Go to your phone's Bluetooth settings, find the Xiaomi Smart Band 9 Pro, and unpair it. Afterward, return to the Mi Fitness APP and try adding the device again;
3. If the above steps don't work, uninstall and then reinstall the Mi Fitness APP. Once installed, open the APP again and allow a minute for the data to sync, as previously missing data can take a short time to reappear;
4. Make sure both the Mi Fitness APP and the band’s firmware are up-to-date, as outdated versions can cause connectivity issues.