‘WiFi not connected to network’

Everyday between 4 and 6 pm, our internet slows to a crawl and the. We get the message ‘WiFi does not appear to be connected to the internet.  However, it is.  I’ve tried restarting the gateway, as well as power cycled the modem/router.  Yet it continues to happen almost daily.  It’s extremely frustrating, especially because when I go to the xfinity app, it shows all is fine.  All pictures attached

.  How do I Fix this issue, for what my bill is, this shouldn’t be happening.