Why Emails Bounce (and How to Stop It)

Every bounce is more than a failed delivery.
It’s a lost sale. A wasted send. A little scar on your sender reputation.
Stack up enough of them and you’re not just losing today’s revenue — you’re slowly locking yourself out of your customers’ inboxes.

The Two Types of Bounces

Not all bounces are equal — but they’re all bad news.

Hard bounces are permanent failures. The address doesn’t exist, the domain’s gone, or the inbox is dead. Once you hit a hard bounce, that address is useless forever.

Soft bounces are temporary — full inboxes, server downtime, or a recipient’s mailbox on vacation. They might resolve themselves, but repeated soft bounces can tank your sender score just like the hard ones.

Common Causes of Bounces

Most bounce problems fall into three buckets:

• Invalid addresses — typos, fake sign-ups, or addresses that were valid once but aren’t anymore.
• Full inboxes — usually a sign of neglected or abandoned accounts.
• Server issues or blocks — the recipient’s email server rejects your message, sometimes permanently.

And then there’s the sneaky one: catch-all domains. They accept all emails at first, but dump undeliverable ones later, making your bounce rate spike when you least expect it.

The Role of Verification in Bounce Prevention

Bounces aren’t random — they’re predictable if you check before you send.
Verification filters out the junk before it hits your sending platform.
It’s the difference between running a precision-targeted campaign and lobbing emails into the void.

At TLDR Verify, we don’t hedge. We tell you exactly which emails are safe to send and which are dead weight — no “catch-all,” no “unknown.”

• Proven at Sopro: Our live campaigns run at a 0.8% bounce rate — that’s 99.2% delivery — across millions of sends.

That’s not “pretty good”; it’s industry-leading. And it’s entirely down to verifying with certainty, not guesswork.

Stop Letting Bounces Kill Your Campaigns

The longer you send without knowing exactly what’s on your list, the more damage you do.
Run your addresses through TLDR Verify, cut your bounces, and protect your sender score before it’s too late.