Starter Template Enabling error

Hi.
I successfully installed the Starter Templates v. 2.6.6 but when I tried to enable it I got this error:

Fatal error: Uncaught TypeError: ftp_fput(): Argument #1 ($ftp) must be of type resource, null given in /var/www/html/puli/wp-admin/includes/class-wp-filesystem-ftpext.php:212 Stack trace: #0 /var/www/html/puli/wp-admin/includes/class-wp-filesystem-ftpext.php(212): ftp_fput() #1 /var/www/html/puli/wp-content/plugins/astra-sites/inc/classes/class-astra-sites-importer-log.php(73): WP_Filesystem_FTPext->put_contents() #2 /var/www/html/puli/wp-includes/class-wp-hook.php(292): Astra_Sites_Importer_Log->has_file_read_write() #3 /var/www/html/puli/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters() #4 /var/www/html/puli/wp-includes/plugin.php(484): WP_Hook->do_action() #5 /var/www/html/puli/wp-admin/admin.php(175): do_action() #6 /var/www/html/puli/wp-admin/site-health.php(15): require_once(‘…’) #7 {main} thrown in /var/www/html/puli/wp-admin/includes/class-wp-filesystem-ftpext.php on line 212

I don’t have any other plugin installed (it’s a new fresh wordpress installation)

My server’s details is:

WordPress 5.7.2
Server Linux 4.19.0-16-amd64 x86_64
Apache/2.4.38
Php 8.0.5
Php memory limit 256M
Curl 7.64.0 OpenSSL/1.1.1d
Database 10.3.27-MariaDB-0+deb10u1

Could anyone help me?
Thanks a lot.
Best regards