Ubuntu 18.04 and usernames.

Hi I know it is mushroom season so maybe it is that but the said OS is creating users with user@tld.com rather than just user.tld

Also been have an amazing issue with smtp; 554 5.7.1 <@.com>: Relay access denied … on one virtual server. From Gmail etc.

Yet mail for other domains working fine on same server. Googled all and tried all.

IP was listed on blacklists but have grovelled and all seems fine now, it was an IP my ISP gave me.

I am running a home server for the first time behind my ISP router.

Any ideas would be great.

Thanks.

New Centos install and same, also my other servers, what is going on? Have I missed something?

Ok found the answer here but I have no idea how this got changed on my servers?

https://www.virtualmin.com/documentation/email/pop-and-imap

Actually seems it is related to the html5 theme. It is what it defaults to for some reason?