Yes — you can connect a domain you already own instead of registering a new one through Maildoso.
How to connect an existing domain
In your dashboard, go to the Domains page and choose Connect existing domain, then follow the steps shown.
You can also add external domains via the API — your API token is under your profile icon → Settings → General.
Once the domain is set up on our side, we'll give you two nameservers to add at your registrar — this step is required, not optional. We manage all DNS for the domain (MX, SPF, DKIM, DMARC) ourselves; you don't add or edit those records yourself — see How DNS records work for your Maildoso domains.
Nameserver rule: set only our two nameservers at your registrar — nothing else. Extra or leftover nameservers (or none at all) will stop us from generating DNS for the domain and it won't work. For the full walkthrough, timing, and troubleshooting (including DNSSEC, which can block delegation even when the nameservers look correct), see My domain shows "NS Not Set" — what does this mean?
Domains registered through Cloudflare Registrar
Domains registered through Cloudflare Registrar (not just using Cloudflare for DNS) can't have their nameservers changed away from Cloudflare, so they can't be connected to us unless you transfer the registration to a registrar that allows nameserver changes. A domain that merely uses Cloudflare's DNS but is registered elsewhere is fine to connect as-is. See Using domains registered with Cloudflare Registrar for the full picture.
Re-adding a domain you previously removed or transferred out
If a domain was connected to Maildoso before, was later removed or transferred to your own registrar, and you're now trying to add it back as an external domain, this can sometimes fail even though the domain is active and working fine elsewhere. This usually means our side still has a stale record for that domain from before. Contact support with the domain name and roughly when it was originally removed or transferred — we'll clear the old record so it can be reconnected.
Still stuck, or not sure whether your domain qualifies? Contact us and we'll help you get it connected.