When the ecobee loses the connection to the internet, and the router password doesn’t work, the best way to fix the problem is to remove the ecobee from the wall, waiting 30 seconds for it to reboot, then putting it back on the wall. To remove it from the wall, gently pull straight back. There are 4 tabs on the corners and two sets of pins that need to aligned when putting it back on the wall. The unit should connect to wifi automatically.