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Fixing Cloudflare 521 Error: Enable Origin Pull Setup - Stop Nginx Redirect Loop with These Checks-How to Fix Port 8080 Allocated Error in Docker

Updated 2026-07-28 23:26:17developer-tools

Fixing Cloudflare 521 Error: Enable Origin Pull Setup - Stop Nginx Redirect Loop with These Checks-How to Fix Port 8080 Allocated Error in Docker

Likely symptom

Likely cause

Safe rollback

Verification route

Repeat the original action, not only a simplified test case.
Restart the app or reload the service after configuration changes.