Installation problem investigations

Hi everyone,
I endly discover something that makes my osp install working!
my url is https://drone.sdis80.fr, and all my users get an email as [email protected]. And that is not working. I don’t know why. But I tried with users who have an email that is not in sdis80.fr domain, and everything works fine.
My conclusion is that there is a problem when you have a domain for the server and the same domain for your email. Does someone facing the same issue ?