1. Make sure that the SSL certificate has been configured correctly: First, make sure that you have obtained a valid SSL certificate and configured it correctly on the Nginx server. Ensure that the path and file name of the certificate file are correct and that the certificate contains a public key and a private key.

Configure Nginx to listen for HTTPS requests: Open Nginx's configuration file. In this file, find or add a server block that HTTPS listens to.

3. Restart Nginx service: After saving the configuration file, restart Nginx service with an appropriate command to make the configuration changes take effect.

4. After completing the above steps, when accessing https, Nginx will use the default HTTPS port 443 to provide secure connection without explicitly specifying the port number.