==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.9
- Deployed with iRedMail Easy or the downloadable installer? Download
- Linux/BSD distribution name and version: Debian 9 Stretch
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB (MySQL)
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I am trying to add an alias, and am currently using Rainloop to send mail. I have gone through this guide (https://docs.iredmail.org/sql.create.mail.alias.html) to add an alias, and make sure it was on the authenticated list with the plugin enabled, but I still get the error below:

postfix/submission/smtpd[8218]: NOQUEUE: reject: RCPT from localhost[::1]: 554 5.7.1 <**EMAIL**>: Recipient address rejected: Sender is not same as SMTP authenticate username;

How can I set this up so I dont have to make a mailbox for every email address I want to send from?