When setting up your Meross smart device, you need to grant Precise Location and Local Network to Meross app, or you will encounter error in the picture below even if you are connected to the device Wi-Fi.
All you need to do to fix this issue is
1. Go to Settings and find Meross app and edit Permission as picture below.
Note: Android phones are the same. Go to settings and enable Location and Local Network in Permission.
2. Make sure you enabled Precise Location.
3. Go back to Meross app and retry. You will find the issue will be gone.
Please do not disable these two permissions, or you will find your devices unreachable in Meross app.