Hi @LeZèbre typically the www. version will redirect to the non-www. version, I have confirmed this to be the case for your website.
When I checked the link you provided it redirects to mydomain.com, but if I type it in manually as zebrestrategie.com it does work and the www. is redirecting as well (this is what you want).
I would recommend removing the www. subdomain from HubSpot and changing it to something relevant, like info.zebrestrategie.com
To do this, disconnect the domain here:
The domain in HubSpot is currently configured as a redirect domain, you’ll need to connect it as a primary domain for email following these steps:
1 - click Connect a domain:
2 - choose Email Sending:
This requires a paid plan:
3 - follow the prompts to connect your email sending domain:
Looking at your screenshot, it looks like you are on a free plan - if you don’t want to upgrade, you can still send emails from HubSpot, it will allow you to send from any email address for users in your account or you can add an address:
This will not prompt you to set up the DMARC, DKIM, or SPF records for HubSpot.
DMARC can be setup independent of the host, it’s a record type you add directly to your DNS:
Add a TXT record with HOST = DMARC, with this value = v=DMARC1; p=none;
SPF is automatically added by HubSpot since it’s being sent from their server, no action needed (see more here from the recent AMA)
You won’t be able to configure a DKIM record, but you can send a test email from HubSpot using https://www.learndmarc.com/ to better understand your email deliverabilty.