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Cloudflare 521 Error: Troubleshooting and Fixes - Docker Container Exits Immediately: 'Command Not Found' Error Fix-Nginx Rewrite Rule Loop: Diagnosis and Solution

2026-07-28 14:21:36
Cloudflare 521 Error: Troubleshooting and Fixes - Docker Container Exits Immediately: 'Command Not Found' Error Fix-Nginx Rewrite Rule Loop: Diagnosis and Solution

Result check

  • Keep one change per test run so you know which step helped.
  • Undo temporary changes after the issue is confirmed.

Next references

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