Unplug the Chromecast from the power source
Wait 10 seconds
Plug the Chromecast back in
Wait for it to restart
If needed, restart it from the Google Home app
Open the Google Home app
Select your Chromecast device
Tap Settings
Tap More
Tap Reboot
Unplug the Chromecast from the power source
Wait 10 seconds
Plug the Chromecast back in
Wait for it to restart
If needed, restart it from the Google Home app
Open the Google Home app
Select your Chromecast device
Tap Settings
Tap More
Tap Reboot