Issue in Postfix /etc/postfix/main.cf file. mydestination didn't update the localhost.domain.com with my updated domain

Installed the free version of Virtualmin GPL on a clean install of Ubuntu 20.04. Didn't change my Contabo VPS servers default hostname before the install. So changed the hostname after the install with Webmin. While configuring Postfix I noticed /etc/postfix/main.cf in the mydestination parameter didn't update all the way with my new domain.. It had a localhost.contabo.net value that was the default from my VPS Contabo. It didn't' change to localhost.mydomain.com with Webmin hostname update. Don't know if it broke anything but just changed it manually.