Why can't I install even if I have the required PHP version?

I want to install Drupal 9.0.2 on a server with Apache2 and PHP 7.3.2.
I am getting this error.

Your PHP installation is too old. Drupal requires at least PHP 7.3.0. See the system requirements page for more information.

The version I get with php -v is the following.

PHP 7.3.20-1+ubuntu18.04.1+deb.sury.org+1 (cli) (built: Jul 9 2020 16:34:09) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.20, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.3.20-1+ubuntu18.04.1+deb.sury.org+1, Copyright (c) 1999-2018, by Zend Technologies

Why does the installer says the PHP version is too old when php -v says it’s PHP 7.3.20?