Let's Encrypt not issuing www

Hi there,
I've issued an SSL cert using Let's Encrypt for a site and it looks like it's working for example.com but for some reason, it's not issuing www.example.com.

Code:

No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 10 (buster)
Release:        10
Codename:       buster

Code:

PHP 7.3.29-1+0~20210701.86+debian10~1.gbp7ad6eb (cli) (built: Jul  1 2021 16:10:10) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.29, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.3.29-1+0~20210701.86+debian10~1.gbp7ad6eb, Copyright (c) 1999-2018, by Zend Technologies

Can you please help?

Regards,
Devin