ipad connected to home Wifi but cannot access internet

WiFi is functioning fine - all other devices in the home are connecting and have internet access. 

iPad is getting full WiFi signal  (and I'm sitting 15 ft away from the router with no walls in between). 

Through Safari, iPad gets a message like "cannot access website - server not responding".   iPad functions such as "Software Upgrade" also cannot access internet and reach the AppStore (so I don't believe this is a Safari issue)

If I switch the iPad to my AT&T hotspot, everything works fine. 

Any ideas or suggestions?  iPad was at version 13.2 and this problem caused me a lot of problems getting updated to 13.4 but I finally got through the upgrade.