You set up your campaign, hit send, and nothing happens. Or worse - you see a partial send. Maybe 50 emails went out, then stopped. Maybe none at all.

You check your email tool. It says "Active." You check your inbox for bounce messages. Nothing. It's the digital equivalent of screaming into a void.

This isn't random. There are specific, fixable reasons why your sequences aren't sending. And once you know what they are, you can usually solve them in 15 minutes.

Your Email Provider Flagged Your Account as Suspicious

This is the most common culprit. Gmail, Outlook, Microsoft 365 - they all have automated systems watching for sending patterns that look like spam. If you trip those alarms, your provider simply stops sending.

Here's what triggers it:

The fix depends on your provider. Gmail limits you to around 500 emails per day by default, and if you exceed it, it throttles or stops. Microsoft 365 is even stricter - it treats all cold email as potential spam.

If you're using a free Gmail account, the limit is even lower - around 100-150 emails per day. Professional accounts give you more room, but only if you've been warming up the account for 2-4 weeks first.

The real solution here is patience and warmup. You need to spend 1-2 weeks sending regular, back-and-forth emails to real contacts before you start your campaign. Not warmup tools - real emails to people who actually exist. This builds sending reputation.

Your List Has Too Many Bad Addresses

If your bounce rate is high, your email provider starts blocking you. Most providers stop sending entirely once bounces hit 10-15% on a single campaign.

Where do bad addresses come from? Usually, you bought or scraped a list without validating it first. You pulled names from LinkedIn without checking if the email format is correct. You're using a database that hasn't been cleaned in a year.

Run your list through an email validation tool before you send. Tools like ZeroBounce, NeverBounce, or Hunter will cost $50-200 depending on list size, but it's worth it. They'll catch syntax errors, fake domains, and actually-invalid addresses.

Aim for a bounce rate under 5%. If it's higher, your list is the problem.

Your Sending Infrastructure Isn't Configured

If you're sending from a custom domain but haven't set up SPF, DKIM, and DMARC records, your emails won't send. Or they'll send but land in spam. Some email providers will actually block them outright.

This is technical, but it's not optional. You need:

If you're using Gmail or Outlook directly without a custom domain, you're already protected. But if you've set up a sending domain (which you should for any serious campaign), these records are non-negotiable.

Your email service provider should give you the exact records to add to your DNS. Go to your domain registrar (GoDaddy, Namecheap, whatever), find the DNS settings, and paste them in. It takes 10 minutes max. Then wait 24 hours for them to propagate.

If this all sounds foreign, we have a detailed guide on email infrastructure setup that walks through it step-by-step.

Your Email Tool Has a Bug or Rate Limit

Lemlist, Apollo, Hunter, whatever platform you're using - they all have sending limits. Most are reasonable (500-1000+ per day depending on plan), but some have bugs.

Check your tool's dashboard for errors. Look for red notifications, failed deliveries, or accounts flagged as "paused." Some tools auto-pause sequences if they detect authentication issues. Some pause if your bounce rate spikes on a single campaign.

If you see nothing obviously wrong, reach out to your tool's support team with your campaign ID. They can see backend data you can't.

You're Hitting the Mailbox Provider's Hard Limit

Gmail specifically has a "soft" limit and a "hard" limit. The soft limit (which you can push a bit) is around 500 emails per day. The hard limit is non-negotiable.

If you send 2,000 emails in an hour from a Gmail account, Gmail will stop accepting your sends. Sometimes temporarily (a few hours). Sometimes for 24 hours. Sometimes longer if it's a pattern.

The fix: spread your sends across the day. Instead of blasting 500 emails between 9-10 AM, send 50 emails every hour from 9 AM to 6 PM. This looks natural and won't trigger rate limits.

Your email tool should have a setting for this. It's usually called "sending speed" or "emails per hour." Set it to 40-60 per hour maximum.

Your Campaign Is Paused (And You Forgot About It)

I'm half-joking, but this happens more than you'd think. You set up a sequence, tested it, then accidentally hit pause while reviewing the settings.

Check your campaign's status page. Is it showing as "Active," "Running," or "Paused"? If it says paused, click resume and you're done.

What To Do Right Now

Run through this checklist in order:

If you're still stuck after checking all of these, the issue is probably specific to your tool or provider. Contact their support with your campaign details.

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