IPhone can't connect to wi-fi?

My house currently has 2 internet connections. My iphone can only connect to one of the internet connections and can't connect to the other one. The one it is connected to is horribly slow and I need to connect to the better one. But, everytime I try to connect to it, a loading icon appears (next to the routers name in the Wi-Fi section of the settings app) and gets stuck on it for hours. Anyone know how to fix this?

Added (1). I just reset my network on the settings app and it worked.

Either you do not have permissions to connect to the faster one or you do not have the proper user name and password entered. You need to get those issues validated. If neither of these work, the DHCP pool may be insufficient.