In previous versions of stalwart, dns records were presented in a simple to read and copy dns fields.
Since 0.16, stalwart now just text dumps you the zonefile, even in jmap API. I feel like this should be put back to a more structured table approach for users who manually manage their DNS or even have other applications which use this API.
Also adding a system to check that the domains DNS records are correct and present would also be useful for checking what could be wrong with domain email settings.