If you’re using Emailable to clean up your mailing list, you’ve probably seen some cryptic validation errors pop up. Maybe you’re trying to cut down on bounces, or your boss is bugging you about deliverability. Either way, you want answers, not vague warnings or endless trial and error.
This guide is for anyone who’s run email lists through Emailable and hit a wall. I’ll break down the most common validation errors, show you what actually matters, and help you fix issues without getting lost in technical jargon.
Why Email Validation Errors Happen
First, a reality check: no email validation service is perfect. Emailable does a decent job, but it’s not magic. Here’s what’s really going on:
- Syntax checks: Is the email address formatted correctly? Obvious, but easy to mess up.
- Domain checks: Does the domain exist and accept mail? Not every domain with an “@” is real.
- Mailbox checks: Does the specific inbox exist? This is where things get tricky.
- Spam trap/role account checks: Is the email likely to get you blacklisted or ignored?
Each layer is another place for errors to pop up. Some are easy to fix, others aren’t worth stressing over.
Common Email Validation Errors in Emailable (and What They Mean)
Emailable gives you a validation “result” and sometimes a reason. Let’s break down the ones you’re likely to see, what they really mean, and what you can (or can’t) do about them.
1. Invalid Syntax
What it means: The email address doesn’t follow the basic rules (missing “@”, invalid characters, etc.).
How to fix it: - Scan for typos — double “@@”, missing dots, weird symbols. - Watch for copy-paste errors from spreadsheets.
Pro tip: Don’t trust form submissions. People type fast and make mistakes.
Ignore: If you’re importing from a source you don’t control (like a legacy CSV), just filter these out. They’ll never work.
2. Invalid Domain
What it means: The part after the “@” isn’t a real domain, doesn’t resolve, or doesn’t accept mail.
How to fix it: - Double-check for typos in the domain (e.g., “gmial.com”). - Search the domain in a browser. If it doesn’t exist, the email’s no good.
What to ignore: Sometimes marketing teams use fake domains for test signups (“test@asdf.com”). Just drop these.
3. Disposable or Temporary Email
What it means: Someone used a throwaway address from sites like Mailinator or Guerrilla Mail.
How to fix it: - Filter these out immediately. They’re not worth emailing.
Pro tip: If you’re seeing a lot of disposables, look at your signup process. People use these when they don’t want to give you their real email—maybe your incentive isn’t clear, or your form is too pushy.
4. Role-Based Email Addresses
What it means: Addresses like info@, sales@, or support@. These often go to a team or alias, not a person.
How to fix it: - Decide if you care. If you’re running a customer support list, you might want these. For marketing, they usually perform poorly. - Most people just suppress them from bulk sends.
Ignore: Don’t get too hung up here. Sometimes a role account is legit (small businesses do weird things).
5. Catch-All Domains
What it means: The domain is set up to accept any email sent to it, whether the inbox exists or not.
How to fix it: - You can’t know for sure if a specific address is real. It’s a coin toss. - Send a test email. If you get a hard bounce, suppress it.
Pro tip: If you’re risk-averse, exclude catch-alls from your main campaigns. If you’re cleaning a small list, you might take your chances.
6. Accept-All Server / Unverifiable
What it means: The mail server accepts every address, or won’t tell Emailable if the mailbox exists.
How to fix it: - Not much you can do. This is an industry-wide limitation, not a bug in Emailable. - Watch your bounce rates if you email these addresses. Suppress the ones that bounce.
Ignore: No validator will solve this. If deliverability is your top concern, treat these as risky.
7. Mailbox Full
What it means: The inbox exists, but it’s over quota.
How to fix it: - Try again later, but don’t get your hopes up. These rarely clear out. - Suppress or mark as inactive after repeated failures.
Pro tip: If it’s a valuable contact (like a customer), reach out another way.
8. Spam Trap Suspected
What it means: The address looks like it could be a trap maintained by ISPs or anti-spam groups.
How to fix it: - Remove these from your list immediately. - Don’t try to “fix” them. If you hit a spam trap, your sender reputation can tank.
Ignore: Any list with lots of these is probably outdated or bought. Clean it up or start over.
9. Greylisted / Temporary Failure
What it means: The server temporarily rejected validation (maybe it’s overloaded, or rate-limited).
How to fix it: - Wait a few hours and revalidate. - If it keeps failing, treat it as risky.
Pro tip: This isn’t a permanent error. Don’t panic on the first try.
10. Unknown / Unable to Validate
What it means: Emailable couldn’t figure it out—maybe the server didn’t respond, or gave an ambiguous answer.
How to fix it: - Try again later. Sometimes it’s just a timing issue. - For big lists, suppress these if deliverability is critical.
Ignore: Every validator spits out some “unknowns.” Don’t chase your tail trying to get to 100%.
How to Actually Troubleshoot (Step by Step)
Let’s say you’re looking at a batch of validation results and your head’s spinning. Here’s how to make sense of it:
- Export Your Results
- Get a CSV or Excel file from Emailable with the result and reason columns.
- Sort and Filter
- Group by result (e.g., “invalid,” “catch-all,” “disposable”).
- Tackle the worst offenders first: invalid syntax, invalid domain, disposable, spam trap.
- Decide What to Suppress
- No-brainers: invalid, disposable, spam trap.
- Consider suppressing: catch-all, accept-all, unknown—especially for cold outreach or new campaigns.
- Keep: valid, mailbox full (with a warning), role-based (if it fits your audience).
- Fix What You Can
- Typos in domains? Manually correct if you recognize them (e.g., “gamil.com” → “gmail.com”).
- For bulk lists, don’t waste time trying to rescue every oddball address.
- Test and Monitor
- Send a small batch to the “risky” segment (catch-all, unknown) and monitor bounces.
- Adjust your suppression rules as needed.
- Iterate
- Clean your list regularly. One-and-done doesn’t work—people change jobs, inboxes die.
What Works, What Doesn’t, and What to Ignore
- Works: Suppressing invalid, disposable, and spam traps. These are dead weight.
- Sometimes Works: Catch-alls and unverifiable addresses. Worth a test if you need every possible contact, but don’t expect miracles.
- Doesn’t Work: Trying to get to zero bounces. Even the best tools miss stuff.
- Ignore: Chasing perfection. Focus on the big, fixable problems first.
Pro Tips for Smoother Email Validation
- Validate on signup: Don’t wait until after the fact. Use Emailable’s API at the point of entry.
- Communicate with your team: Make sure everyone knows which errors mean “never email” vs. “maybe try later.”
- Don’t buy lists: If your list is full of spam traps and disposables, the problem isn’t your validator.
- Don’t obsess over catch-alls: You can’t outsmart servers that hide mailbox existence.
Keep It Simple, Iterate Often
Email validation isn’t about chasing a mythical “perfect” list. It’s about avoiding the obvious landmines and keeping your sender reputation clean. Focus on the errors that matter, ignore the noise, and check your list every so often. The tech will never be perfect, but your process can be.
If you keep it simple, most email headaches are easy to fix. And if not—well, at least you’re not stuck guessing what “catch-all” means anymore.