Identifying Dead Mailboxes: Key Signs and Reaction Time

·Aug 05, 2025 03:41 PM·

When do you know your mailboxes are dead and how quickly do you react? Is it when reply % drops significantly even if mailbox health shows 100% on Instantly?

4 comments

· Sorted by Oldest

Jason H.
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Following
Adam A.
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hey petar and crew, it’s a combination of factors. we have alarm bells for things like 4+% bounce, suddenly getting less replies on the exact campaign that was doing well, and running placement tests. We react instantly, have inboxes we rotate in even if it just seems like a fluke
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Petar R.
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How many emails you need to send before looking at reply rate?
DK A.
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Hey Petar R., if reply rates suddenly drop even when Instantly shows 100% health, it’s definitely a red flag. We watch for bounce rates over 4%, a decrease in replies on previously strong campaigns, and also run placement tests. Typically, we assess reply rates after sending around 300–500 emails. Happy to share more if it helps!
1

Jason H.
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·
Following
Adam A.
·
·
hey petar and crew, it’s a combination of factors. we have alarm bells for things like 4+% bounce, suddenly getting less replies on the exact campaign that was doing well, and running placement tests. We react instantly, have inboxes we rotate in even if it just seems like a fluke
1
Petar R.
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How many emails you need to send before looking at reply rate?
DK A.
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Hey Petar R., if reply rates suddenly drop even when Instantly shows 100% health, it’s definitely a red flag. We watch for bounce rates over 4%, a decrease in replies on previously strong campaigns, and also run placement tests. Typically, we assess reply rates after sending around 300–500 emails. Happy to share more if it helps!
1