nginx: [emerg] "user" directive is not allowed here in /etc/nginx/conf.d/vincent.conf:1

The error message you encountered indicates that the "user" directive is not allowed at the specified location in the "/etc/nginx/conf.d/vincent.conf" file.

The "user" directive is used to specify the user and group that the nginx worker processes should run as. However, it should be placed in the main nginx configuration file, typically located at "/etc/nginx/nginx.conf", rather than in individual configuration files within the "/etc/nginx/conf.d/" directory.

To resolve this issue, you can follow these steps:

1. Open the main nginx configuration file using a text editor:

sudo nano /etc/nginx/nginx.conf

2. Locate the "user" directive in the file. It should be placed at the top-level context, outside of any other blocks.

3. Move the "user" directive to the appropriate location within the main configuration file.

4. Save the changes and exit the text editor.

5. Verify the nginx configuration for any syntax errors:

sudo nginx -t

6. If the configuration test is successful, restart the nginx service:

sudo systemctl restart nginx

By ensuring that the "user" directive is placed in the correct location within the main nginx configuration file, you can resolve the error and start the nginx service successfully.