Can not create the Maildir structure within my home directory is to send an email with the s-nail command

The problem may be due to the absence of a correctly configured mailbox for the user myuser on your Ubuntu server. Postfix needs this mailbox for storing and managing emails.

To ensure proper Postfix configuration and mailbox setup, please follow these steps:

1. Create the myuser user if not already present:

sudo adduser myuser

2. Switch to the myuser:

sudo su - myuser

3. Manually make the Maildir directory:

mkdir -p Maildir/{cur,new,tmp}

4. Switch back to root user:

exit

5. Now, retry your command:

echo 'init' | s-nail -s 'init' -Snorecord myuser

For more in-depth information, you can always refer to Postfix docs:

https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-postfix-on-ubuntu-22-04#step-1-installing-postfix

Hope that this helps!