Bounce rate too high: the thresholds to respect and how to bring it down
A high bounce rate almost always comes from where the addresses came from, not from your campaign. But some "bounces" aren't bounces at all: they're refusals from your own email provider, and the addresses are valid. The two are handled very differently.
| Normal rate | under 5%, ideally around 3% |
| Watch zone | 6 to 7% |
| Red zone | 10% and above: stop the campaign |
| Database decay | about 20% invalid addresses in six months |
| Detection time | usually within the hour, sometimes up to 48 hours |
Hard bounce, soft bounce, false bounce
A bounce is an email refused with a non-delivery report. What matters is who refused it, and why.
| Type | What happens | Examples |
|---|---|---|
| Hard bounce | The address doesn't exist, or no longer exists. | Typo, person who left the company, guessed address. |
| Soft bounce | The recipient's server refuses temporarily. | Mailbox full, server unavailable, message flagged as suspicious (attachment, link, low-rated IP). |
| False bounce | Your own provider refuses to send. The prospect's address is valid and they received nothing. | Hourly or daily quota exceeded, account blocked for excessive sending. |
Emelia doesn't distinguish hard from soft: either way, the contact leaves the sequence. The exact reason is written in the rejection message. Read it in full before drawing conclusions.
Where to read your bounce rate
In the campaign, Performance tab: the Bounced line gives the count and the rate, overall and step by step. The Dashboard also shows a Bounce Rate for the period you pick. In your lists, these contacts have the Bounced status.
The rate is calculated on emails sent. A contact can move from "opened" to "bounced": some servers accept the email, then send a non-delivery report a little later.
In the previous version of Emelia, the rate at the top of a campaign was calculated on every contact in the list, including those not yet contacted: it looked much lower than the step 1 rate (for example 6% against 25% for the same bounces). To judge what has already gone out, rely on the rate based on emails sent.
The usual cause: the data
When bounces are genuine address refusals, the problem lies in where the file came from, almost never in the campaign.
- Purchased lists.
- Old files: a database loses about 20% of its validity in six months (people leave, change roles, domains are dropped).
- Addresses rebuilt by hand from a guessed pattern (firstname.lastname@…), or a guessed generic address.
- External waterfall enrichment, which maximises the number of addresses found rather than their reliability.
- Domains that accept every address ("catch-all"): the address can't be checked in advance.
The Email Finder only returns validated addresses, with a bounce rate of around 2 to 3%. If you see an abnormal rate on addresses found by Emelia, write to support with the list name. See Finding your contacts' emails.
False bounces: when your provider refuses to send
Telltale signs: addresses that were verified, bounces grouped around the same hours, a message that mentions a limit, a quota or the sender. Here are the messages our support sees most often.
| Message excerpt | Who refuses | What it means |
|---|---|---|
| "exceeded the max emails per hour" | Your provider (seen at o2switch: about 180 per hour for the whole domain) | The domain's hourly quota is exceeded, all mailboxes combined. The excess is discarded. |
| "exceeded the limit of 200 messages per hour and per account" | OVH | 200 messages per hour for the whole OVH account, all domains combined. |
| "too many messages in 120h" | Small providers | A cap of about 50 emails a day. |
| "Message blocked" | The provider's outbound filter (Hostinger) | Sending flagged as suspicious before it even leaves. |
| "Reject for policy reason: Spam detected" | Gandi | Automated sending detected. |
| 550 5.4.6 "Unusual sending activity detected" | Zoho | Unusual activity: contact Zoho, add spintax. |
| 550 5.1.8 | Microsoft | Account flagged for sending spam: follow Microsoft's unblock procedure. |
| 550 5.7.708 "traffic not accepted from this IP" | Microsoft | Low-reputation IP, especially on a new or trial Microsoft 365 tenant. |
| 550 5.7.1 "rejected per SPAM policy" | Consumer internet providers (SFR, Orange…) | Your own mailbox's spam filter blocks the send: an address unsuited to outreach. |
| 554 5.7.1 | Often the recipient's server | Frequently a misconfigured DMARC on your side. |
What to do about false bounces
- Cut the volume per mailbox sharply. If blocks keep coming: pause for 24 hours, then halve all your quotas. Providers enforce hourly, daily and sometimes monthly caps.
- One mailbox, one campaign, and 3 mailboxes per domain (5 at most). With a provider that caps per domain or per account, the total is what counts: 40 mailboxes on one domain, each in several campaigns, will break any quota.
- Recover the contacts. Once the cadence is fixed, filter contacts with the Bounced status, export them and import them into a new campaign. When importing, don't map the status column: otherwise they stay "Bounced" and are skipped again.
- In the long run, switch providers for sending: Google Workspace and Microsoft 365 don't have such tight quotas. See My emails land in spam.
It's never Emelia's IP: a mailbox connected through the Microsoft connection sends via Microsoft's API. The refusal comes afterwards, as a non-delivery report. Move to a paid licence assigned to each mailbox, wait about a day, then ask Microsoft support for an exception if the error persists. Don't restart warm-up or the campaign in the meantime.
What Emelia does with a bounced contact
- It leaves the sequence: it gets no more emails from this campaign.
- Unless your sequence plans for it: with the If email bounces condition, the contact continues down the branch you set (towards LinkedIn, for example), with no new email.
- It keeps the Bounced status. If you reuse the same list in another campaign, it's skipped automatically.
- It isn't added to your blacklist: if the same address turns up in another file, nothing stops it. Add it to the blacklist to exclude it everywhere.
- No credit is refunded for a bounce. The Email Finder, for its part, only charges for addresses it finds.
Not even a soft bounce. Every new attempt damages your domain's reputation a little more. The only exception: false bounces caused by your provider's quota, whose addresses are valid.
Cleaning a database before sending
- A list from elsewhere: run it through Emelia's email verification (Lead Lists, select the leads, then Verify). It costs 1 credit for 4 verifications, charged on every row whatever the result.
- A deliberately strict result: when in doubt, the address is marked invalid. A "valid" address can be trusted.
- Consumer addresses (Gmail, Hotmail, Yahoo) can't be verified: they come out invalid. They're not suited to B2B outreach anyway.
- Emails found by Emelia are already verified: no need to run them through the verifier again.
- A database older than six months: verify it again, or better, run the extraction again.
Pause the campaign, identify where the addresses came from and change the source. Sending on damages the domain's reputation for all your mailboxes.
Frequently asked questions
The questions we get asked on this topic, answered briefly.
Will contacts that bounced because of my provider's quota be resent automatically?
No. Once bounced, a contact leaves the sequence. Fix the cadence first, then export the contacts with the Bounced status and import them into a new campaign, without mapping the status column.
Why is my bounce rate different on the dashboard and in the campaign?
The dashboard covers the period you pick and all your campaigns, the campaign only its own sends. In the old interface, the rate at the top of a campaign was also calculated on every contact in the list, which made it lower than the per-step rate.
I get "temporary delivery problem" notices for an address I don't know. Is that serious?
No. It's almost always an address from the warm-up network. Google retries the send several times on its own, hence the impression of looping bounces, with no effect on your campaigns. If the same address keeps coming back, report it to support.
Do Mailinblack challenges count as bounces?
No, and not as replies either: the prospect only receives the email once the challenge is solved, and the sequence carries on. You can solve them by hand, or switch on Resolve Mailinblack automatically under Settings, Advanced (1 credit per solved challenge). Leave these emails in your main inbox so Emelia can find them.
Does a bounce cost me credits?
The bounce itself costs nothing, but no credit is refunded for an address that bounces. The Email Finder only charges for addresses it finds, and they're verified before being returned to you.