Find what's failing
When your bounce rate turns amber or red on the Overview, two tabs show you where the problem is. Both follow the date range and domain filter you chose at the top of the page.
- Bounce summary answers three questions in order: when are bounces happening, why, and at which mailbox providers.
- Breakdown lets you cut all your results by domain, provider, reason or server reply.
Select a chart point, bar or table row to open the affected messages in Activity.
Bounce summary tab
The headline row
The bounce rate with its health label, the total number of recipients that bounced, and the count for each bounce type:
| Type | Meaning |
|---|---|
| Hard | The address or domain does not exist. |
| Blocked | The mailbox provider refused the mail as spam, or because of policy or reputation. |
| Soft | A temporary problem such as a full mailbox, a message that is too large, or mail that expired because the receiving server kept deferring it. |
| Stopped by SendMero | SendMero stopped the message, for example because the address was already suppressed. |
The total includes expired mail, so it matches the Bounced tile on the Summary tab.
Bounce Timeline
Bounced recipients over time, stacked by type. Point to a bar to see every type for that day or hour. Select a bar to see those messages in Activity.
Bounce Reasons
A bar chart of the reasons the receiving servers gave (for example Invalid recipient or Spam block), coloured by bounce type. Underneath, a short note for each type that occurred says what it means and what to do:
- Hard: remove those addresses now. Mailbox providers punish sending to addresses that don't exist more than almost anything else.
- Blocked: check SPF, DKIM and DMARC, slow down sending to that provider, and review your list quality and content.
- Soft: no action for one-offs. Stop sending to recipients who soft-bounce repeatedly.
- Stopped by SendMero: nothing to fix in the mail itself; check why those recipients were stopped.
Select a bar to see the messages with that reason.
Which mailbox providers?
The bounce rate at each mailbox provider (Gmail, Microsoft, Yahoo, Apple and other), with the provider that bounced the most first. Amber and red bars are above the warning and at-risk limits. Select a bar to see that provider's bounced and expired messages.
Each of the three charts has View as table.
Breakdown tab
Five tabs, each showing the 20 biggest rows. Anything beyond that is added together in one Other row, which has no link.
| Tab | What it shows | Use it to |
|---|---|---|
| Domains | Delivered, bounced, expired, deferred and complained recipients, plus bounce and complaint rates, for each sending domain. | Find a sending domain that is hurting your results. |
| Mailbox providers | The same figures for Gmail, Microsoft, Yahoo, Apple and other providers, based on where the recipient's mail is hosted. | See whether one provider is blocking you while the others are fine. |
| Bounce reasons | Bounced recipients by bounce type and the reason the receiving server gave, including Message expired. | Learn why mail is bouncing. |
| SMTP responses | The most common replies from receiving servers, with bounced, deferred and expired counts and one example reply. | Look up an exact code such as 550 5.7.1 and read what the server said. |
| Deferral reasons | Why receiving servers asked SendMero to try again later, with the SMTP code, the number of attempts and an example reply. | Spot rate limits or greylisting before they turn into bounces. |
Reading the numbers
- Counts are recipients, not messages. A recipient who bounced on several tries counts once. Attempts on the Deferral reasons tab counts every retry.
- Share is the part of all recipients on that tab that the row accounts for.
- Bounce and complaint rates on the Domains and Mailbox providers tabs show a Warning or At risk label using the same limits as the Overview. A row needs at least 100 recipients with a final result before it gets a label, so a handful of bounces from a tiny domain doesn't raise an alarm. Point to a rate to see the numbers behind it.
- Unknown appears for older results recorded before mailbox providers were tracked.
Example responses
Example responses come from the receiving server. SendMero hides email addresses and IP addresses in them, replacing them with [address] and [ip], so you can share a screenshot with your team. To see the full response for a message, open it in Activity and check its timeline.
Open the messages in Activity
You can open Activity from:
- a point on the Volume chart (the Delivered or Bounced line for that day or hour). View as table has a View button on each row if you prefer the keyboard;
- a bar on the Bounce Timeline, Bounce Reasons or Which mailbox providers? charts;
- a row in any Breakdown table.
Activity opens with the same date range and, if you chose exactly one domain on the Overview, that domain. The extra filters appear as chips under From Overview, for example Outcome: Bounced, Mailbox provider: Gmail, Bounce type: Soft or SMTP code: 550 5.7.1. Remove a chip to widen the search, or press Clear to start over. Chips can be removed with the keyboard too: Tab to a chip and press Enter or Backspace.
Normally Activity filters by when SendMero received a message. When you arrive from the Overview with an outcome such as Bounced, the date range applies to when that outcome happened, the same way the Overview counts it. A message received last week that expired yesterday is listed for yesterday's range.
If you picked more than one domain on the Overview, Activity opens without a domain filter because it can only filter by one. Choose the domain in Activity if you need to narrow it.
What to do next
- A single domain with a high bounce rate: check how its list was collected and stop sending to addresses that hard-bounce.
- A single provider with many Blocked bounces: read the example reply on the SMTP responses tab. It usually links to that provider's guidance for senders.
- Many Invalid recipient hard bounces: remove those addresses and use confirmed opt-in so typos never reach your list.
- Frequent deferrals from one provider: send at a steadier pace and avoid sudden jumps in volume.