Device and Chromecast are on the same network, device still not recognizing my Chromecast:

• This solves my issue: Make sure your devices are not running VPNs or Firewalls
• Turning the Chromecast, mobile device, and router off and on again at the same time can actually resolve many casting related issues. First, try turning off your Chromecast by unplugging it, and while it’s unplugged power off your mobile device and home router. Keep everything off for about 1 minute.
• Turn your router and/or cable modem back on, and wait for the connection to fully reestablish about 2 minutes.
• Turn on your Chromecast
• Turn on your mobile device
• Once all devices have fully powered on, check again to see if the casting icon has appeared

Google help: http://bit.ly/3mpmXe5