[Observium] Change base_url listening port

Hi Observium team:

We are trying to follow the “Config Option” under:

https://docs.observium.org/config_options/

to change the Observium GUI port from default 80 to 8000, by updating “config.php” to:

// Change web interface port setting

$config['base_url'] = "http://%22.$_SERVER%5B%22observium.abc.com%22%5D.%22:%22.$_SERVER%5B%228000"];

But it doesn’t work even after reloading apache2.

Any suggestion how to make it right?

Thanks. - Gordon