If this is the usual iPhone can't connect to your router question, Apple iPhones can forget connections, I mean you use the menu in the setup of the WiFi to forget the old connection and then connect again.
If your name and password fail then on your PC/Apple login to your router to see what the router password is.
But here's where it gets murky. You asked about the name and password. So take some time to clear up what the issues are.