Welcome to the Apple Discussions.
A few things to try when having issues like this, in order of use:
1. Make sure the router firmware is up to date.
2. Reboot the router by full power off and on.
3. Reboot the iPad by full power off and on.
4. Reset WiFi on the iPad, Settings > WiFi > forget the network and then reinstall the network info by hand.
It is very important to check and make sure the router is using fully updated firmware, especially since you said you are able to connect at other hotspots.
Hope this helps.
Ralph