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heads-up platform & cms 3 sources 1 min read

Cloudflare HTTP 5xx Errors Hit South Korea and Montreal Sites

What happened

Cloudflare customers experienced two separate incidents of increased HTTP 5xx errors across different regions in late April. On April 30, users in South Korea observed elevated 5xx error rates between 12:40 and 13:00 UTC, affecting sites served through Cloudflare's Korean infrastructure. Two days earlier on April 28, Cloudflare's Montreal (YUL) data center experienced increased HTTP errors from 04:55 to 05:25 UTC. Both incidents lasted approximately 30 minutes and were resolved without additional user action required.

Business impact

Enterprise sites using Cloudflare CDN in these regions likely experienced user-facing errors, abandoned sessions, and potential revenue loss during peak business hours in Asia. Teams may have faced false alerts from monitoring systems detecting the infrastructure-level failures rather than application issues.

Background

HTTP 5xx errors indicate server-side problems that prevent successful page loads, often appearing as generic error pages to end users. Cloudflare serves as CDN and security layer for millions of enterprise websites, making regional outages particularly visible to monitoring systems. The South Korea incident occurred during local business hours, while the Montreal outage hit during North American overnight periods.

What this means for your team

Review your CDN failover procedures and ensure monitoring systems can distinguish between application errors and infrastructure provider issues. Configure alerts to account for Cloudflare status updates before triggering incident response procedures. Document which business-critical sites rely on Cloudflare and establish communication protocols with stakeholders when CDN-level issues occur rather than application problems.

What to watch

Monitor Cloudflare's status page for patterns of regional instability, particularly if your user base concentrates in affected regions. Watch for any follow-up communications about root cause analysis or preventive measures.

Sources

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