The server is temporarily unable to handle the request, often due to overload or maintenance.
Quick facts
When does it occur
The server is temporarily unable to handle the request, often due to overload or maintenance.
It belongs to the 5xx Server Error class of responses, defined in RFC7231#6.6.4.
Browse all codes in this class: 5xx Server Error
How to fix it
Add health checks, scale capacity, and use Retry-After so clients retry later.
Common causes
How to fix it
Double-check the URL, return to the homepage and search again, or retry later.
Add health checks, scale capacity, and use Retry-After so clients retry later.
Check service logs and health, confirm upstream dependencies, restart or scale if needed, then verify monitoring alerts.
Frequently asked questions
503 belongs to the 5xx Server Error class and is generally not cached for long; behavior is controlled by Cache-Control.
5xx Server Error: The server is temporarily unable to handle the request, often due to overload or maintenance.
Sources & standards
Updated 2026-08-18
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