Maindomain must contain legal info or Maildomain must be different from Maindomain

[utzer]

Hello all,
I hope everyone has a good 2021!

My YunoHost server

Hardware: Some VPS
YunoHost version: 4.0.8.3
I have access to my server : Through SSH | through the webadmin
Are you in a special context or did you perform some particular tweaking on your YunoHost instance ? : no

Description of my issue

Some of my emails are bounced by one of the major email providers in Germany. I have done the setup as well as possible, DNS configuration is done as per suggestions of Yunohost. This mail provider requires these two things:

“…In particular, we recommend choosing a host name that indicates its
usage as a mail server (eg. mail.example.com) and to ensure the host’s
domain leads to a website providing full contact details…” <<–!!

Unfortunately “example.com” does not yet meet these requirements because
there is no legal contact information at “example.com”.

I think mainly the legal info is the problem.

Now the problem I have is either:
a) I need to add contact details to the main domain.
OR
b) I need to have the mailserver main domain to be different from the main domain.

How do others deal with this requirement, especially that it is very reasonable to have contact details on a webpage that you host? It is even required by law in many countries I believe.

What I have done so far:
I did set up a new domain mail.example.com, I set up an application on that new domain in the main path (Bludit) to serve a page with contact/legal information. Which works fine. I can open mail.example.com and it will show the Bludit blog main page.
Then I made that domain (mail.example.com) my main domain via the admin webinterface, which worked fine. Now the mailserver has a cert for mail.example.com as oposed to before it had one for example.com.

But now when I try to login as a user I can’t succeed. I think there is now some loop that just takes me back to the login page again… and again… and again, each time I can login, not fault shown. (I made sure the password is correct, I even set a new password by the admin interface.
I can reach the login page by either going to https://mail.example.com/yunohost/sso/ or by going to https://example.com, which will forward me to https://mail.example.com/yunohost/sso/?r=YpD9PPSQv2y2n48MFVyw5aGHa=

Any tip is welcome, I wrapped my head around this for quite some time since last year (yesterday), but am not sure how to solve this.

[utzer]

I realized this question is pretty hard to answer, still hoping for some good tips or even questions!

[Limezy]

Couldn’t you edit the html of the main Yunohost page (example.com) to add contact details on it ?
Would this solve the issue or did I misunderstand your problem ?

[utzer]

How would I edit the user portal that is served on the main domain?

Yes, this would solve the problem. I think what would be generally nice would be to be able to add a footer link to the user portal (aka login page), with a name to choose and a destination link.

[utzer]

OK, this might have been a technical issue which involved me missing to clear cookies. I will check further and leave results here.

[utzer]

Alright, let me summarize this.

1. You can host a application on the main domain, so I now have the main domain mail.example.com and and configured some BLUDIT blog for that domain and with the path / so now when I go to mail.example.com it will provide some legal contact information.
2. The SSO does work again. I can go directly to its bath mail.example.com/yunohost/sso or to some domain of Yunohost that is not used at all, which then forwards to mail.example.com/yunohost/sso as well.
3. This problem was cause by my assumption that Yunohost could not serve any page on the main domain.

It works now.