Please make sure your iOS is connecting to the 2.4GHz of your home Wi-Fi and you are having iOS 13 or later. Restart your iOS will help due to some system cache issue.
You can learn more here.
(1)Make sure the air filter is properly in place with plastic packaging removed.
(2)Check and clean/replace the air filter.
（1）Make sure the air filter is properly in place with plastic packaging removed.
（2）Tap the power button to increase the fan speed.
（3）Make sure there is enough space on all sides of the air purifier.
（4）Clean or replace the filter.
When you replaced a new filter, you need to reset the filter life cycle in Meross app.
Generally, you should replace it every 3-6 months. It also depends on your air environment, daily use time and fan speed. For your convinience, Meross app would send you notifications when the filter life cycle comes to under 20%,10% and exhausted. So, open the notification of Meross app and feel free to use your air purifier.