I have run into this problem a few times.
Here's been some cause's
Safari browser /Solution/ Installed Chrome browser.
Network and it's limitations/ School networks and corporate network's like staples, best buy,.. just to name a few; these networks have firewalls that block the network ports your device uses to connect to forums or even block many functions of connecting to online storage servers.
So just make sure your connected to a no rules WiFi connection and have a browser that can
make life a little easier and a lot faster, and let me know how it goes.