Thanks for reaching out and sorry to hear that you are having an issue with your Chromecast. Let's check on this further.
A few questions — what's the LED light status in your Chromecast? Are you getting any messages when reconnecting it to your network? Were there any recent changes in your WiFi network? Please restart your WiFi router and Chromecast device. If the issue still persists, reset your Chromecast.
Let me know how it goes.
Just checking in to make sure that you've seen my response. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.