Lists subdomain make compaign spammed

As I installed 3.6.10 on my lists.MYDOMAIN.fr and set domain name MYDOMAIN (the related website, and parent domain), lists.MYDOMAIN make email test campaign as spam.
Furthermore “View in browser” is lined to my website not the lists.MYDOMAIN.
As ViewInBrowser plugin doesnot allow to get ony url parameters, I am stucked …
I do not have cthe issue with another website and the lists.MYDOMAIN as web adress parameter

Thanks a lot in advance

@sherpadawan When you use phplist on a subdomain and assuming that you access phplist at lists.mydomain.fr/admin

on the Settings page, website address should be lists.mydomain.fr
in config.php, $pageroot should be an empty string

$pageroot = '';`

Yes i’m accessing phplist at lists.mydomain.fr/admin
in my config_extended.php (which is include in config.php)

$pageroot=‘’

I think it is an email header issue.