About 502 Errors...
502 Errors are often caused by issues between online servers over which you have no control. However, since it is possible there's something wrong on your end, here are some fixes to try:
Re-submit the listing without attaching photos or video files. Instead, email photos to email@example.com or text to 806.341.7080
Try loading the URL again by pressing F5 or Ctrl-R on your keyboard, or by clicking the refresh/reload button.
Start a new browser session by closing all open browser windows and then opening a new one. Then try submitting again.
Try another browser. Popular browsers include Firefox, Chrome, Internet Explorer, and Safari, among others.
Call 1.800.381.4848 during business hours if you need assistance.