Meaning
The upstream server didn’t respond in time.
Causes
- Upstream latency
- Network delays
- Long-running operations
Fixes
- Retry later
- Contact the owner if it repeats
Example
HTTP/1.1 504 Gateway Timeout
FAQ
- How is it different from 502?
502 is invalid response, 504 is timeout. - What if it persists?
Check upstream server health.
Contact
Check status/support if it’s urgent.