Short answer: no. Maildoso's sending relay strips List-Unsubscribe and List-Unsubscribe-Post headers from every outbound message, on every plan. This is intentional platform behavior and not something we can turn on for your account or a specific domain.
Why we strip these headers
List-Unsubscribe headers are built for high-volume bulk/marketing senders, and inbox providers use them as one signal to separate "bulk mail" from person-to-person mail. On a B2B cold outreach platform, keeping them out of the header set is part of how Maildoso mailboxes keep looking like normal 1:1 sending rather than a bulk mailer — which protects inbox placement for everyone sending through our shared infrastructure. Because the header is removed before the message is signed, it's also never part of the DKIM signature. If a checker tool shows the header or its DKIM coverage missing, that's expected — nothing is misconfigured on your end.
What to do instead
Put a clear, visible unsubscribe link or opt-out instruction directly in the body of every campaign email — for example in your signature or footer. This satisfies CAN-SPAM and most B2B cold email compliance requirements even without a List-Unsubscribe header.
Keep your own suppression list in your sequencer (Instantly, Smartlead, etc.) and honor opt-outs promptly whenever someone replies "unsubscribe" or clicks your link.
If you're chasing Gmail/Yahoo's one-click unsubscribe mandate specifically: that requirement targets very high-volume bulk senders (roughly 5,000+ messages/day to a single provider). Typical B2B cold outreach volumes on Maildoso aren't the use case it targets — a body unsubscribe link plus a clean, honored suppression list is the compliant path on this platform.
Related: PTR and DKIM are managed the same way
This is the same design principle behind two other things customers sometimes ask us to change: we don't publish PTR/reverse DNS records for sending IPs, and DKIM is fully managed with no selector you configure yourself. See A checker tool says my PTR or reverse DNS (rDNS) is failing and How DNS records work for your Maildoso domains. None of these are bugs, outages, or something a plan upgrade changes — they're how the shared sending infrastructure is built to protect deliverability for everyone on it.
When to contact support
You don't need to contact us just to confirm this behavior — it's expected on every account, every domain, every plan tier. Do reach out if you're seeing an actual deliverability problem (spam placement, bounces, or a drop in replies) so we can review your specific sending pattern, or if you need written confirmation of this behavior for your own compliance review.