How to Troubleshoot an Unreachable Web Page or API
Local Environment
Check if your network status is OK and if you can access other websites.
Try a different browser or clear browser cache.
Check if the HOSTS file maps the domain name to 127.0.0.1 or an incorrect IP address. You can see what IP address the domain name is mapped to with the following command line.
ping {your_domain} |
Check if you are using a HTTP proxy or if the proxy can access the website.
DNS Settings
Check that the A record of the DNS configuration points the domain name to the correct IP address.
Cloud Host
Check if the cloud host is on and accessible. You can use the following command line to check if cloud host is on.
ping {IP_address} |
Check if the HTTP (80) or HTTPS (443) port is allowed in the firewall.
telnet {IP_address} 80 |
Check that the reverse proxy server listening on port 80 or 443 is running. You can find out what process is using 80 or 443 with the following command line.
sudo lsof -i -P -n | grep LISTEN |
Check if the configuration of the reverse proxy server is correct.
Check if the actual web project is up and running. You can view all processes with the following command line.
ps -ef |
Check that the cloud host operating system has sufficient resources such as CPU, memory, disk, and bandwidth. You can view the resource usage of the cloud host in the cloud platform console or view usage by command lines.