Why: 504 That’s an Error – Google YouTube
Did you receive an error (504) from Google while browsing around YouTube or Google hosted website? This error seems to happen when you click on different pages loading a lot of content quickly. In detail, an HTTP 504 error is a Gateway Timeout Error and usually happens when a webserver cannot process an HTTP request in a timely fashion to your web browser.
504. That’s an error.
The server encountered a temporary error and could not complete your request.
Please try again in the 30 seconds. That’s all we know.
Per Google, just reload the page right away and you should be OK. Otherwise, no need to wait the full 30 seconds – you can safely try again in 5-10 seconds.
*IF* you are currently experiencing this issue, use the comment form below to let us know and see if others are also reporting the same error at the same time.