If that is the case, you should raise the size limits for post_max_size and upload_max_filesize directives.
Two options:
1.- The hard way
For example, if your default php version is 8.2, you should edit file /etc/php/8.2/fpm/php.ini and in that file search for post_max_size and upload_max_filesize directives and change the value for the one that fits your needs.
Example:
post_max_size = 50M
upload_max_filesize = 50M
Save the file and restart the service.
systemctl restart php8.2-fpm
2.- The easy way.
From Hestia Web UI, go to Server settings and there hover your mouse around your php service and once the pencil icons appears, click on it: