A sender bounce means your email was blocked on its way out, usually because the inbox provider has fingerprinted your copy. To fix it, launch a new campaign with a clean list from ListKit and add far more spintax and variants. If bounces stay high after that, contact support about rotating your inboxes.
TL;DR
Sender bounces usually mean your emails have been fingerprinted: the same copy has gone to so many people that the inbox provider recognizes it and blocks it.
Your leads are usually fine. The problem is the email, not the list.
First fix: launch a new campaign with a clean list from ListKit, and add a lot more spintax and variants.
Last resort: if bounces are still high, contact support about rotating your inboxes. This costs money, so try the first fix first.
What is a sender bounce?
There are two kinds of bounce:
Type | What happened | Usual cause |
Sender bounce | Your email was blocked before it reached the lead. | Your copy has been fingerprinted. |
Hard bounce | The lead's email address doesn't exist. | The person left their job or the company changed domains. See Why is my bounce rate high and how do I fix it? |
Fingerprinting happens when the same subject line and body go out to thousands of people with little or no variation. The inbox provider learns to recognize that message and starts blocking it, even to valid addresses.
How to fix it
Step 1: Launch a new campaign with a clean list and much more variation
Don't keep sending the fingerprinted copy. Instead:
Start a new campaign. Don't just edit the old one.
Use a clean list from ListKit. Pull fresh leads rather than reusing the leads from the campaign that bounced.
Add way more spintax. Spin whole sentences, not just single words, across the subject line and the entire body. For example: {I noticed you're hiring for sales|Saw you're growing the sales team|Looks like your sales team is expanding}. The more combinations, the harder your email is to fingerprint. The AI spintax option in the sequence editor (100 credits) can do this for your whole script. See How do I use spintax, including AI spintax?
Add more variants. Write several genuinely different versions of each email (different opening line, angle and call to action) so no single version goes to too many people.
Step 2: If bounces are still high, contact support about rotating your inboxes
If your sender bounce rate is still high on the new campaign, send us a message in the app and we'll talk through rotating your inboxes. Our support team replies Monday to Friday, 8am to 5pm ET.
Only do this after Step 1. Rotating inboxes costs you money, and most sender bounce problems are fixed by Step 1 alone.
Expected outcome
Your new campaign sends copy that isn't fingerprinted, and sender bounces drop.
You only pay for inbox rotation if a fresh campaign with heavy variation doesn't fix it.
FAQ
Why are my emails sender bounced?
Usually because your copy has been fingerprinted. The same email went to too many people with too little variation, so the inbox provider started blocking it.
Is a sender bounce the same as a hard bounce?
No. A hard bounce means the lead's email address is invalid. A sender bounce means your email was blocked on the way out, even though the address is usually valid.
Are my leads bad?
Usually not. Sender bounces come from your copy, not your list.
Why start a new campaign instead of fixing the old one?
The old campaign's copy is what's been fingerprinted. A new campaign with a fresh list and heavily varied copy gives you a clean start.
Are my inboxes burned? Do I need new ones?
Not necessarily. Try Step 1 first. Rotating inboxes costs money and usually isn't needed.
How much spintax is enough?
Spin every sentence of the subject line and body, not just the greeting, and run several variants of each email.