Try going into Settings >> Wi-Fi and delete (Android uses the term 'Forget') your home WiFi entry on one of your phones and then try to add it back in.
<br> If that doesn't work out, try installing this 'RouterCheck' app:
<br>
<a href='
https://play.google.com/store/apps/details?id=com.Sericon.RouterCheck.client.android&amp;hl=en' target='_blank' class='externalLink' rel='nofollow'>
https://play.google.com/store/apps/details?id=com.Sericon.RouterCheck.client.android&amp;hl=en</a>
<br> It will check your router settings, mostly for security issues, but in each topic there's some really good, extensive documentation with basic definitions, and possible fixes for problems. If you're not really comfortable delving into your wireless router options this is a really good app to guide you along. Anyway, the default settings in your Comcast modem/router might require some tweaking to work better with your phones.
<br> You might also want to install this Netalyzer app, it will run a thorough analysis on your home network:
<br>
<a href='
https://play.google.com/store/apps/details?id=edu.berkeley.icsi.netalyzr.android&amp;hl=en' target='_blank' class='externalLink' rel='nofollow'>
https://play.google.com/store/apps/details?id=edu.berkeley.icsi.netalyzr.android&amp;hl=en</a>
<br> This app won't focus so much on your router but more on performance issues with your home network connectivity.
<br> Of course maybe all this doesn't even matter. Have you contacted Comcast? There could be something on their end. Using a web browser try going here to run a bandwidth test on your connectivity:
<br>
<a href='
https://speedof.me/' target='_blank' class='externalLink' rel='nofollow'>
https://speedof.me/</a>
<br> The download and upload speeds should be close to the values stated in your Comcast plan level, but also pay attention to the latency number. (higher numbers for the speed are better, but a lower number for latency).