Bounce rate
Bounce rate is the share of sent emails that bounced. For reputation, the hard bounce rate is the one to watch.
How it affects cold email
A rising bounce rate usually means a list is old, bought or unverified. Mailbox providers read it as a sign you don’t know your recipients. Fix the list before sending more, not after.
Microsoft recommends removing invalid addresses regularly to cut bounces and complaints (Microsoft).
How Inboxed handles it
- A mailbox pauses itself when more than 5% of its recent emails hard-bounce (once it has sent at least 20), and a campaign when more than 8% do (after at least 50). Both show the reason and resume when you choose.
- You also get an alert when a workspace’s bounce rate over 24 hours is above 5% and more than twice its rate over the previous 7 days.
Related terms
Sources
Sources checked on 8 November 2026. Rules change, so check the source before you rely on a detail.
- Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders · Microsoft Tech Community
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