Cloudflare 520–526 Errors Explained: Causes and Fixes
What Cloudflare's 520, 521, 522, 523, 524, 525, and 526 errors mean, why they happen between Cloudflare and origin, and how to diagnose and fix each one.
June 23, 2026
6 min read
5xx Server Errors: 500, 502, 503, 504 Explained
Understand 500, 502, 503 and 504 server errors, diagnose application, proxy and upstream causes, and monitor status, body and error-rate patterns.
May 27, 2026
17 min read
5xx Error Rate Monitoring: Thresholds and Alerting
Monitor 5xx error rates with ratio-based alerts, route and dependency breakdowns, burn-rate context, and an on-call playbook for 500–504 failures.
May 11, 2026
16 min read