Fix "service nginx restart" failing

What is Nginx?

Nginx is a web server. It is the program that answers visitors and sends them your pages. When you change its settings, you restart it. If a restart fails, Nginx stays off and your website does not load.

Step 1: Read the error

1. Connect to your server with SSH.
2. Run:

systemctl status nginx

This shows if Nginx is running and prints the last messages.

3. For more detail, run:

journalctl -xe

This shows the newest system log lines. Press q to leave.

Step 2: Test the settings

Most failures come from a typing mistake in a settings file.

nginx -t

This checks all settings without starting anything. It tells you the file and line with the problem. Typical mistakes are a missing semicolon, a missing curly bracket, or a wrong file path.

1. Back up the file before you edit it.
2. Open the file named in the message.
3. Fix the line.
4. Run nginx -t again until it says the test is successful.

Step 3: Check if the port is busy

A port is a numbered door on the server. Web traffic uses doors 80 and 443. If another program holds one, Nginx cannot start. You may see "Address already in use".

ss -tlnp | grep -E ':80|:443'

This lists which program is using those doors. Often it is Apache. Stop the other program, or change one of them to a different port.

Step 4: Check the disk

A full disk can also stop Nginx. Check it:

df -h

If a disk shows 100 percent, free up space. Old log files are a common cause. Do not delete files you are unsure about.

Step 5: Start it again

systemctl restart nginx

This restarts Nginx. Then check your website in a browser.

Quick recap

• Read the error with systemctl status nginx.
• Run nginx -t to find setting mistakes.
• Check for a busy port and a full disk.
• Restart only after the test passes.