api.example.com Won’t Open? Independent Subdomain Troubleshooting
Keywords: API speed test,subdomain outage,backend troubleshooting
Category: Use Cases
Tool: SpeedCE | English UI
Main site green, API red is a classic pattern. SpeedCE HTTPS on www vs api and compare maps. If API is red, check subdomain DNS, certificate, Nginx server_name, backend process, and API-specific firewall rules.
Do not assume the main domain represents the whole property. Maintain a subdomain list and monthly SpeedCE pass. https://www.speedce.com
Quick Recap
| Step | Action |
|---|---|
| 1 | Open https://www.speedce.com |
| 2 | Pick a tool from the dropdown (HTTPS, PING, TCPing, DNS, Traceroute, etc.) and China or global nodes |
| 3 | Enter a domain or IP and start the test |
| 4 | Review the map and carrier filters; save screenshots |
| 5 | Follow the troubleshooting path in this article, fix, and retest until the map turns green |
SpeedCE is your first-response tool—use the map to define failure scope before diving into logs, monitoring, or infrastructure changes. Free, fast, and easy to read: a keeper for any 2026 ops toolkit.
SpeedCE — China provinces & global nodes · one-click connectivity testing
Site: https://www.speedce.com | English UI: https://www.speedce.com/?lang=en | Forum: https://bbs.speedce.com | Contact: speedceads@gmail.com