Address not found issue

I've setup the IRedMail server with vultr and it's working fine but the emails are not being sent or received on the email it's shows the message as : "Address not found"
for the email I've setup with iRedMail, pls help me in the attached file I've added the logs

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====

- iRedMail version : iRedMail-1.7.2

- Deployed with Downloadable installer

- Linux/BSD distribution name and version:  Ubuntu 22.04.3 LTS

- Store mail accounts in which backend : MySQL

- Web server: Nginx

- Manage mail accounts with iRedAdmin-Pro : No

- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.