I'm sorry for the trouble this may have caused you — let's check this out.
A few questions: are you using a private or public network? Also, what's the exact message you're getting when connecting your Chromecast to your network
Give these steps a try:
Looking forward to your response.
Just checking in to make sure that you saw my response. I'll be locking this thread if we won't hear back from you again in 24 hours. Should that happen, feel free to create a new one if you have more questions or have other concerns in the future.