Next time you have problem opening your site or find HTTP error 504, you may want to contact your ISP
I was getting HTTP error 504 while trying to open this site. The problem was strange in the sense that the same sites that were able to open in the morning were not opening post even
ing. First I tried taking help from Google, found this CheckUpDown. None of the solution provided there could help. Tracert clearly indicated that trouble lies with web host as the path was getting aborted at the web host’s end. So,had a rapid mail exchange with the web host.
In the last mail they pointed out to check with the ISP (Internet Service Provider). To my surprise that turned out to be the culprit. Within two days my ISP solved the problem that was lurking around for more than 2 weeks.
Now you know whom to contact, the next time you see HTTP 504.
Related posts:
- How to block the window that opens up every time you open Reliance NetConnect?
- How to resolve blogger error bX-xvu2n5?
- How to find the URL of a twitter message?
- Generate mobile version of your blog or site for free
- CommentHunt: Find do follow blogs and increase your PageRank
Ankur Jain, founder of a web start-up, long-time blogger and proud owner of the "Learn" series of websites. 
[...] from Google we can be assured of reliability of these tools. I had faced this issue in the past and I can tell you it becomes quite annoying when neither you nor your ISP, webhost are able to [...]