The short answer
There are two categories of deliverability problems. Authentication failures (fixable in one day). And reputation problems (takes weeks to build, minutes to destroy). Commune handles authentication automatically. Reputation is determined by your sending behavior.Category 1: Authentication failures
Inbox providers check three DNS records before delivering email:
When you add a custom domain to Commune, all three are configured automatically. You add the DNS records, Commune verifies them, and all outbound email is DKIM-signed from that point forward.
If you’re using the shared
commune.email domain, these are already set up.
Category 2: Reputation signals
Authentication tells providers the email is legitimate. Reputation tells them whether recipients want it. Inbox providers look at:
Bounce rate is the percentage of emails that couldn’t be delivered. High bounce rate means you’re sending to bad addresses. Above 5%, Gmail and Outlook start filtering to spam.
Complaint rate is the percentage of recipients who click “report spam”. Above 0.1% (1 in 1000) is dangerous. Above 0.3% can get your domain blocked.
Domain warmup
New domains have no reputation. Start sending 500 emails/day from a fresh domain and every one goes to spam. Warmup is the process of gradually establishing trust:
Commune handles warmup automatically. When you create a new inbox on a new domain, the warmup schedule starts immediately. You don’t configure it. If you try to send more than the current warmup limit, Commune queues the excess.
What Commune monitors automatically
- Bounce and complaint rates per inbox (via Resend webhooks)
- Automatic suppression list (bounced addresses never receive again)
- Sending health gate: if bounce rate exceeds 5% or complaint rate exceeds 0.1%, sending is automatically paused
Check your inbox health
healthy, warning (approaching thresholds), paused (thresholds exceeded, sending stopped).
The AI email fingerprint problem
LLMs produce similar patterns. “Hope this finds you well”, consistent structure, similar word frequency. Inbox providers are detecting these patterns. The fix: emails need to be genuinely wanted by recipients. Personalization helps. But the most important signal is whether people actually open and engage — that only happens if you’re sending to people who opted in or have a reason to want the email.Related
Delivery Monitoring
Track bounce rates, complaint rates, and inbox health metrics across all your agent inboxes.
Why Agent Emails Land in Spam
Detailed technical deep-dive into deliverability signals and how to fix them.