Rebooting your Chromecast or Google TV Streamer may fix several issues. There are a number of ways to reboot your Google streaming device:
Chromecast, Chromecast Audio and Chromecast Ultra
From the Google Home app
- Make sure your mobile device or tablet is linked to the same account as your Chromecast.
- Open the Google Home app
.
- Tap and hold your device's tile.
- At the top right corner, tap Settings
More settings
.
More settings 
From the power source
- Unplug the power cable from the Chromecast device.
- Leave it unplugged for ~1 minute.
- Plug the power cable back in.
Note: Unplugging the Chromecast from the TV’s HDMI port does not reboot the device. It must be disconnected from the power source in order to reboot.
Chromecast with Google TV
From Google TV
- Using your Chromecast Voice Remote, navigate to the upper right of your TV screen
Settings
.
- Select System
Settings 
.From the power source
- Unplug the power cable from Chromecast with Google TV.
- Leave it unplugged for one minute.
- Insert the cable back into Chromecast with Google TV.
Note: When you unplug Chromecast with Google TV from the TV's HDMI port, it does not reboot the device. It must be disconnected from the power source in order to reboot.
Google TV Streamer (4K)
From the Google TV Streamer Voice Remote
- Press the Power button
once to turn off your Google TV Streamer.
- Wait for about eight seconds or more.
- Press the Power button
From Google TV
- At the top right of your TV screen
All settings
.
- Select System
All settings 
.From the power source
- Unplug the power cable from Google TV Streamer.
- Leave it unplugged for one minute.
- Insert the cable back into Google TV Streamer.
Note: When you unplug Google TV Streamer from the TV's HDMI port, it doesn't reboot the device. It must be disconnected from the power source in order to reboot.