Internet

First. Please try starting here if you wish;

https://forums.xfinity.com/conversations/your-home-network/connection-troubleshooting-tips/602da777c5375f08cdea3db9 

Hello user_cjuodp, thank you for your post, we appreciate your time, and I am here to help.

Are there any devices that are staying connected? Do you have any devices connected to your modem by ethernet cable? Do you have an idea of how far away from your modem the devices that are not staying connected are from the modem, are there walls, or similar things in the way?

@user_cjuodp 

Have you had a chance to see if any of those troubleshooting tips apply ?