Connection to home wifi.

We have 2 Nexus 4 phones and have considerable difficulty in getting them to connect to our home wifi. The phone shows 'wifi on' and 'connected' to our router but we can't get/read emails or use any websites. The blue line goes along about a cm then freezes. No problems with Nexus 7 tablet (which doesn't have a sim) and our BP desktop uses the same router with no problems. Have tried a reset and we don't have them all on at the same time. Any help appreciated