If you send bulk emails—whether it’s for newsletters, product updates, or cold outreach—bounces are your enemy. High bounce rates kill your sender reputation and land you in the spam folder (or worse, get you blacklisted). This isn’t just a “nice-to-have” thing to fix. It’s make-or-break for your email results.
This guide is for anyone who’s tired of guessing why emails are bouncing and wants a practical, no-nonsense way to analyze and reduce those bounces. We’ll break down how to use Glockapps bounce tracker, what you should actually care about in the data, and what’s mostly noise.
Why Bounces Matter (and What Most People Get Wrong)
Let’s get this out of the way: not all bounces are created equal. You’ve probably seen “hard” and “soft” bounces before. Hard bounces mean the email address is flat-out undeliverable (think: fake or dead). Soft bounces are usually temporary issues—full mailbox, server busy, etc. But if you ignore either one, you’re asking for trouble.
The real danger? Internet Service Providers (ISPs) and email services see repeated bounces as a sign you’re a spammer, even if you’re not. Too many bounces, and your deliverability tanks across the board.
Here’s what most people miss: - It’s not just about removing dead emails. You need to know why addresses are bouncing. - Fixing bounces isn’t a one-time thing. Lists go stale, servers misbehave, and users fat-finger their signups. It’s ongoing.
Step 1: Setting Up Glockapps Bounce Tracker
First, you need to actually track bounces reliably. Inbox screenshots and “delivered” stats from your email platform won’t cut it—you’ll miss the reasons behind bounces.
Here’s what you do: 1. Sign up for Glockapps: It’s a paid tool, but it’s one of the few that actually breaks down bounce data in a way that’s useful. (Forget free tools that only show “delivered” or “not delivered.”) 2. Integrate your sending platform: Glockapps works with most major email services (Mailchimp, SendGrid, Amazon SES, etc.). You’ll need to hook up your SMTP server or email API credentials. Their setup guides are pretty clear, but expect some copy-pasting of API keys or SMTP settings. 3. Set up bounce tracking: Glockapps gives you a unique “bounce address”—an email address that catches bounce notifications. You’ll need to set your email service’s “Return-Path” or “bounce address” to this, so Glockapps can read the bounce reports as they come in.
Pro tip:
Do a test campaign to a small sample before rolling out bounce tracking to your whole list. Make sure bounces are being caught and reported as expected.
Step 2: Running a Campaign and Collecting Bounce Data
Once you’re set up, send your next campaign as usual. Glockapps will start logging bounces in near real-time.
What you’ll see in your Glockapps dashboard: - Total sent - Total bounces - Hard vs. soft bounces - Bounce reasons (the actual error messages from recipient servers) - Breakdown by domain (e.g., Gmail, Yahoo, corporate domains)
What matters: - Bounce rate: Under 2% is good. Over 5%? You’ve got a problem. - Patterns by domain: If Gmail is blocking you but Outlook isn’t, you’ve got a reputation issue with Gmail specifically. - Weird spikes: Sudden increases in bounces could mean a list problem, a technical misconfiguration, or a blacklisting.
What doesn’t matter: - One-off soft bounces. These happen. Focus on patterns, not exceptions.
Step 3: Making Sense of Bounce Reasons
Here’s where most tools fall short, but Glockapps is actually helpful: it shows you the real bounce messages.
Typical bounce reasons you’ll see (and what to do about them):
- User unknown / mailbox not found: The email address doesn’t exist. Remove these ASAP.
- Mailbox full: Could be temporary, but if it keeps happening, take them off your list.
- Spam-related blocks: “Message rejected due to content” or “Blocked by policy.” This means your sender reputation or content is triggering filters. Time to review your subject lines, content, links, or sending patterns.
- Domain or IP blacklisted: Your sending server is on a blacklist. Don’t ignore this—fix it before sending more.
- Greylisting or rate limiting: The recipient is temporarily refusing your emails. Sometimes, emails will go through on a retry. If it persists, it’s a sign you’re sending too fast or your sender reputation is shaky.
Ignore vague errors like “temporary failure” unless they become persistent. Don’t waste time chasing random blips.
Step 4: Cleaning Your List and Fixing Issues
Now that you know what’s bouncing and why, it’s time to get your hands dirty.
Clean up hard bounces:
- Remove all addresses marked as hard bounces. Don’t think twice—these will never deliver.
- If you’re using a CRM or email platform, export your bounce list from Glockapps and suppress these addresses.
Deal with soft bounces:
- If an address soft bounces repeatedly (say, 3+ times in a row), suppress it. Occasional soft bounces are normal, but persistent ones mean the address is useless.
- For “mailbox full,” you can give it another try in a week or two, but set a cutoff. Don’t leave these on forever.
Fix technical issues:
- If you see a lot of “blocked by policy” or “content rejected” bounces, look into your sending IP, domain reputation, and message content. Use Glockapps’ deliverability tests to see if you’re blacklisted or triggering spam filters.
- Check your SPF, DKIM, and DMARC records. Missing or misconfigured authentication causes all kinds of bounce headaches.
Pro tip:
Don’t get sentimental about old lists. If someone hasn’t opened or clicked in a year, it’s safer to cut them loose than risk more bounces.
Step 5: Using Glockapps to Monitor and Improve Over Time
This isn’t a “set it and forget it” deal. Even the cleanest list gets dirty over time.
Set up ongoing monitoring: - Make bounce tracking part of your regular sending routine. Watch for spikes, especially after importing new contacts or changing content. - Use Glockapps’ alerts to notify you if bounce rates go over a set threshold. Don’t rely on memory—let the tool nag you.
Test before big sends: - Before a major campaign, use Glockapps’ spam testing to see if you’re likely to get blocked or trigger bounces. - Send test emails to seed addresses (Glockapps provides these) to see how different providers handle your emails.
Review and adjust: - If you notice certain domains or segments always bouncing, dig deeper. Maybe your sign-up process is letting in bogus emails, or maybe you need a double opt-in. - Don’t be afraid to prune aggressively. Deliverability is more valuable than list size.
What’s Worth Your Time (and What Isn’t)
Worth it: - Regularly removing hard bounces. - Investigating persistent soft bounces. - Monitoring for reputation issues or blacklisting. - Using Glockapps to catch problems early, before they snowball.
Not worth it: - Obsessing over one-off soft bounces. - Trying to “rescue” dead emails with special tricks. - Paying for “guaranteed deliverability” services that promise the moon. Deliverability is about reputation, not magic.
Wrap-Up: Keep It Simple, Keep It Clean
If you remember one thing: it’s that bounce management isn’t about chasing perfection. It’s about regularly checking your data, cleaning your list, and staying alert for patterns.
Tools like Glockapps make it a lot easier, but no tool can fix a bad list or sloppy sending habits. Keep your lists fresh, watch your bounce reports, and don’t be afraid to cut dead weight. The result? More real people see your emails, and you avoid the silent death spiral of poor deliverability.
Bounces aren’t glamorous, but getting them under control is the fastest way to improve your email results—without needing fancy hacks or wishful thinking.