Right now, you have to invite others to spaces with an email that is sent by the CSM. The problem for us is that we cannot send from our primary domain. We have to send from a subdomain, which we have configured in our instance. All emails we send from this subdomain, from Cockpit or from JO, are delivered as expected.
But we cannot configure Spaces to send from this domain. It is just sent from our main-level domain, which of course does not pass DMARC, SPF, DKIM, etc. and the email is not delivered.
This is to request some flexibility in the way Spaces sends the invites. Please allow us to send invites from our configured subdomain, so that we can actually use Spaces. Right now, this feature is not something we can use, since the invitations never arrive.