If you are using a Comcast supplied gateway device, see this;
Or maybe this link will work and help: https://www.xfinity.com/support/articles/troubleshoot-your-home-network
Thanks for offering the great information, EG, and jav6joev.
Hi Ejphins. Thank you for joining the Xfinity Forums and for creating your first post. If you still need assistance with connecting / authenticating your in home WiFi, I can help. If needed, please feel free reach out to me via private message and include your full name so I can assist you. To send me a private, message click my name (ComcastJoeTru) to view my profile. Then click "Send a message" and private message me.