Sending health: bounce monitoring and pausing a domain

How to do it

1. Open Deliverability. The pill beside the title says what's worst right now: "N critical domains", "N domains on watch", "N domains paused · the rest healthy" or, in green, "All domains healthy". "Checked N min ago" is the age of what's on screen (hover it to see the bounce numbers and the DNS records separately); Re-check All reads both again and says how many domains it re-checked.
2. The stats card doubles as a filter: click Critical or Watch to show only those domains in the table (click again to show all), Sending Domains or Bounced to show every domain, and Authentication to open the Authentication tab. Sending Domains also says how many are healthy; Bounced adds up each domain's latest judged day ("x of y sends · latest day").
3. Under Needs Action there is one card for each client with Watch or Critical domains: a headline such as "Mail from 3 of 5 sending domains is being rejected as spam" or "Bounce rate is climbing on 1 of 3 sending domains", the client and the day, and three numbers — Domains Affected (how many are critical and on watch), Bounced and Policy Blocks. If your mailboxes have no client tags there is one card for the whole workspace. Nothing on watch, no cards.
4. Click Details on a card for What's Happening (that day's sends and bounces, the likely cause and the receivers' most common bounce reply), three Quick Fix steps for that cause, and Worst Right Now — the four worst domains by bounce rate, each marked if it's already paused. See These Domains switches the table to that client's domains.
5. Click Pause N Critical Domains to hold every Active mailbox on that card's critical domains out of rotation. It asks first: "Pause sending on N critical domains? Campaigns keep sending from the healthy ones; resume here when they recover." The card then shows "N paused" with Resume, which puts those mailboxes back. When the likely cause is authentication or sending limits the card also has Fix Authentication (opens the Authentication tab) or Lower Daily Caps (opens Settings → Sending).
6. In the Sending Domains tab, search by domain or client name, pick a status chip — All, Critical, Watch, Healthy, Paused, and Quiet when a domain is quiet — each with its count, and, when your mailboxes carry client tags, pick a client from "Client: All Clients". Rows are sorted Critical → Watch → Paused → Healthy → Quiet, then by bounce rate, and the first 10 show until you click Show All N Domains (Show Fewer folds them again).
7. Click Pause on a domain's row to hold every Active mailbox on it ("Pause every mailbox on <domain>? Campaigns keep sending from your other domains; resume here when it has recovered."), or Resume on a paused domain to put exactly those mailboxes back. A short note at the bottom of the screen says what changed; a note that needs reading — a mailbox marked Disconnected — stays at the top of the page until you close it.

Good to know

• Statuses: Watch from 4% bounced or 1.5% policy blocks; Critical from 8% or 3%; also Watch when a day reaches 2% bounced and more than doubles the days before. Each domain is judged on its latest day with at least 30 sends (days are counted in UTC); with fewer it reads Quiet. A domain whose sending mailboxes are all held by a domain pause reads Paused instead. The footnote under the table states the same lines.
• Each row shows the domain and its client tag, "N/M mailboxes sending" and the most common bounce reply (hover it for the whole reply), the status, Sent (that day's sends, with its date), Bounced (that day, with 7d for the whole week), Policy Blocks, and a bar per day for the last 7 days — green under 4% bounced, grey from 4%, red from 8%, and a stub for a day with no sends.
• "Bounced" counts every bounce message received; "Policy Blocks" are the subset where the receiver rejected on reputation or policy (tagged Blocked in Replies).
• Clients come from the client tag on your mailboxes (Mailboxes → Client Tag). A domain is filed under the tag most of its mailboxes carry; untagged domains go under No Client. You only ever see your own workspace's domains.
• The numbers are read fresh whenever the page loads or you click Re-check All; the hourly check uses the same numbers to raise alerts.
• Pausing sets every Active mailbox on the domain to Paused; Resume puts back exactly those mailboxes and nothing else. A domain pause has no end date — it holds until someone resumes it, from the table or the card.
• Resume follows the same rule as Resume on the Mailboxes page: a mailbox whose connection check failed on its credentials while the domain was paused is marked Disconnected instead of going back into sending — reconnect it to send again. The note reads, for example, "Resumed 4 mailboxes on example.com · 1 needs reconnecting (its last check failed) — it's marked Disconnected.", and the in-app notification says the same (titled "Mailboxes on <domain> need reconnecting" when none went back).
• One incident per workspace: it is emailed once when it opens (subject "Action needed: …" or "Heads up: …"), stays current on the Notifications page while it persists, and a "Deliverability recovered" note appears when every domain is back under the line. Paused domains stay paused until you resume them.
• Likely causes and their Quick Fix: receivers rejecting on reputation → pause the critical domains and resume them after 24–48 hours, halve each mailbox's daily cap when they resume, review the copy and links; authentication failing → fix SPF, DKIM and DMARC in the Authentication tab; bad addresses → verify leads before they're enrolled (bounced leads are already suppressed); provider sending limits → lower the daily cap per mailbox and spread volume across more mailboxes.