Here are three kinds of password involved, Wi-Fi Password, App Password, and Admin Password.
1. How to change Wi-Fi password?
1) If Wi-Fi Password, here is how to change it via webpage version mywifi.mercku.tech
Please login the Mercku webpage mywifi.mercku.tech, select Settings, and then Wi-Fi settings, and here you can change the Wi-Fi name and Wi-Fi password.
2) If Wi-Fi Password, here is how to change it via Mercku App
Please login the Mercku App, select Settings and then Wi-Fi Settings, and here you can change the Wi-Fi name and Wi-Fi password.
2. How to change App password?
Click on 'Login'
Then click on 'Forget password'
After that, click 'Send Pin', the pin will be sent to your phone directly
3. How to change Admin password?
Please factory reset the M2, then set up the Admin password again.