Try each of these solutions in this exact order. If none of these solutions work, feel free to open a support ticket.
1. Check the News and Events Page
Go to 37 New to see if the game you’re playing is undergoing routine maintenance or is experiencing any technical difficulties. If the servers are under maintenance, typically you will have to wait for around one hour.
2. Restart your Browser
Close your browser completely, open it, and try again. You'd be surprised how often this can fix all kinds of problems, and it's quick and easy.
3. Clear your browser's cache, cookies, etc.
And by that I mean clear them, restart the browser, and clear them again. I have no idea why, but there have been numerous times a simple cache clear didn't work. But clearing it, restarting browser, and clearing it again did. If you don't know how to clear your cache check Here for guides on how to do so. You can also use a program like CCleaner to help clear your browser's cache.
4. Update Adobe Flash
Please go to Adobe’s website and download the latest version of Adobe Flash.
5. Try a Different Browser
Generally speaking, Google Chrome and Mozilla Firefox are the best two browsers to use for our browser games. If those two don’t work then try some alternatives. (Opera, Internet Explorer, Safari)
6. Check your connection
Are other websites loading? If other websites aren't loading, then you might not have any internet access. Try resetting your router and modem. Unplug the router and modem and let them sit for 10 seconds before plugging them back in. When you plug these devices back in, start with the modem first. After the modem signal syncs then plug the router back in and turn it on. If this doesn’t work, you might want to consider resetting both your modem and router. Both devices should have small buttons (or pinholes) to completely reset the device.
7. If you still have the problem it's time to get some help!
Please go to the Support Center and open a ticket. Please have your in-game name, server number, and account name handy. The more details you give the quicker and easier our customer support will be able to solve your problem!