How to Debug “Target Endpoint Not Reachable” | Networking & Server Troubleshooting

Source: Dev.to

Are you getting the dreaded “Target Endpoint Not Reachable” while calling an API, payment gateway, or external service?

This video gives you a complete step‑by‑step debugging playbook — the same one used by backend engineers, SREs, and DevOps teams in real production environments. By the end of this tutorial, you’ll know exactly where your request is failing and how to fix it — whether it’s DNS, ports, proxy, TLS handshake, firewall policies, or corporate network rules.

What This Video Covers (Practical & Beginner‑Friendly)

• How to check server connectivity the right way
• Ping, port testing (telnet/nmap), traceroute
• Proxy misconfigurations & how to detect them
• Corporate network firewall issues
• TLS/HTTPS debugging & certificate errors
• Using curl, OpenSSL, Wireshark for deep analysis
• A clean debugging flowchart you can use every time

Who This Video Is For

• Backend developers
• DevOps & SRE engineers
• API integrators
• Payment gateway implementers
• Anyone managing servers or microservices