1. Make sure you're using a modern browser that supports all of the web standards 500px uses. Suggested browsers are Firefox, Google Chrome, Apple's Safari. Ensure you are using the latest version of your chosen browser.

 

2. Clear your cache and cookies and try refreshing the page.

 

3. Make sure your internet provider does not use any kind of traffic shaping or "optimization" service. Some ISPs, such as T-Mobile, take code out of the website in an attempt to speed up traffic, but in fact end up breaking some websites. Call your ISP's tech support line to inquire about this.

If you are still experiencing difficulties, check @500px_Help on Twitter for any service interruption alerts.