My iPhone won't connect to my school's Wi-Fi?

I've been using the same Wi-Fi network, username, and password since I came here in July. I got a the new iPhone 5S in December and everything worked fine until last night when my phone randomly logged me off of the Wi-Fi. I use the same Wi-Fi on my computer and phone, and the password/username still work just fine on my computer. I've tried resetting my network settings and logging in various times but nothing works. All it tells me is that I'm using an incorrect username or password, which is not true. Any suggestions on what I can do?

Not your iphone its the Wi-Fi happens to me too

It happened to me too once, Reboot the Wi-Fi router, then your iphone, and it'll work like before.

Your iPhone is banned in router settings. Go to administrator and ask him to remove the lock.