The users email structure is not correct

Hi there!

I’m using AWS services, My System

Ubuntu 16.04
EC2
Amazon SES

Issue: the user mail has my domain before and after @ like this {xxx.DOMAIN@DOMAIN.com}

I create a user from {Edit Users} in the main domain so my email is {xxx@DOMAIN.com} when I send a message from {SquirrelMail} I received it in my GMail Inbox not in Spam folder so it’s very good but when I reply to this mail the message stuck in GMail mail and I received a reply {Address not found} so I’ve checked my server email and I found it like this {xxx.DOMAIN@DOMAIN.com}

Thanks