Gmail SMTP Not Working? Here’s How to Fix It in Minutes

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Why Gmail SMTP Is So Important

If you’re sending emails through a website, a contact form, or an app like Outlook or Thunderbird, there’s a good chance Gmail’s SMTP server is doing the heavy lifting behind the scenes. SMTP, short for Simple Mail Transfer Protocol, is what allows Gmail to send emails from third-party services—and when it breaks? Everything stops. Imagine your website contact form stops sending messages, your business invoices go unsent, or your email newsletter just vanishes into the void. That’s what happens when Gmail SMTP is not working—and it’s a problem you need to solve fast.

How SMTP Issues Can Derail Everything

This isn’t just a minor tech hiccup. A broken SMTP setup means:

  • Your app can’t send emails.
  • Emails get stuck in the outbox.
  • You lose contact with customers or clients.
  • Forms on your website don’t work.
  • You get bombarded with scary-looking error messages.

Whether you’re running a small business, a blog, or just trying to get your email set up on Outlook, SMTP issues can grind your day to a halt. But don’t worry—we’re going to fix it, step by step.

What Is Gmail SMTP and Why You Need It

SMTP Basics in Plain English

SMTP (Simple Mail Transfer Protocol) is like your email’s personal postman. It’s what takes the message you write and delivers it from your Gmail account to whoever you’re trying to reach.

Here’s the thing: if you’re just sending emails directly from the Gmail app, you probably never think about SMTP. But if you’re using:

  • A WordPress contact form
  • Outlook or Thunderbird
  • A business app like QuickBooks or FreshBooks
  • A custom-built web app

…you need SMTP to send those emails using your Gmail credentials. It’s what powers third-party email sending.

Correct Gmail SMTP Settings (Copy These!)

Here’s what your settings should look like:

  • SMTP Server: smtp.gmail.com
  • Port: 587 (TLS) or 465 (SSL)
  • Username: Your full Gmail address (you@gmail.com)
  • Password: Your Gmail password or an App Password if using 2-Step Verification
  • Encryption: TLS or SSL (depending on the port)

If even one of these is off, your emails won’t go out.

Signs Gmail SMTP Is Not Working

Error Messages You Might See

If your Gmail SMTP setup is broken, you might see these errors:

  • “Could not connect to SMTP host.”
  • “SMTP authentication error.”
  • “5.7.0 Authentication Required.”
  • “Username and password not accepted.”
  • “421: Too many messages sent.”

These messages usually pop up in your email app or website backend. They’re confusing, but they all point to the same thing—SMTP is failing.

Emails Are Stuck in the Outbox or Not Being Sent

Maybe you’re not seeing error messages, but your emails are just… stuck. They sit in your outbox and never leave. That’s another sign SMTP is misconfigured, blocked, or restricted by Gmail.

Third-Party App Issues (Like WordPress or Outlook)

If you’re running a website, SMTP problems can stop your contact forms, newsletters, and password resets from working. On email apps like Outlook or Apple Mail, Gmail SMTP failures prevent outgoing mail completely.

Top Reasons Gmail SMTP Fails

Wrong SMTP Server Settings

This is the most common issue. You might’ve accidentally entered the wrong port, server, or encryption type. One typo and everything breaks.

Always double-check:

  • smtp.gmail.com
  • Port 587 (TLS) or 465 (SSL)
  • Use authentication

Google Account Security Restrictions

Gmail is strict about security—and rightfully so. If Google thinks a sign-in attempt looks suspicious, it might block SMTP access. This happens often with:

  • Brand new app connections
  • Connections from new devices
  • High-volume sending

You’ll need to either confirm the sign-in attempt via your Google account or use app-specific passwords.

Less Secure Apps & 2FA Issues

Google recently disabled access for “less secure apps,” which means apps not using OAuth or 2FA may be blocked. If you’re not using an app password with 2-Step Verification turned on, Gmail will reject the login—even if your password is correct.

Third-Party App Configuration Errors

If you’re using a plugin like WP Mail SMTP, errors in the configuration panel can block email sending. Double-check every field, including sender email, name, and encryption settings.

15 Effective Fixes for Gmail SMTP Not Working

Let’s fix it. Whether you’re running a business, building a website, or just trying to send basic emails through a desktop client, these 15 proven fixes will get Gmail SMTP working again—no IT degree required.

1. Double-Check Your Gmail SMTP Server and Port Settings

This might sound obvious, but it’s the most common mistake. Here are the correct settings again—copy-paste them if you need to:

  • SMTP Server: smtp.gmail.com
  • Port: 587 (TLS) or 465 (SSL)
  • Encryption: TLS (for 587) or SSL (for 465)

Use these exact details or Gmail won’t let your emails through.

2. Make Sure Your Gmail Username and Password Are Correct

Your username must be your full Gmail email address (e.g., yourname@gmail.com).
Your password depends on your account:

  • If you use 2-Step Verification: you need to generate an App Password
  • If you don’t: make sure “Allow less secure apps” is enabled in Google settings

Wrong password = instant failure.

3. Enable “Allow Less Secure Apps” (Only If You Must)

If you’re using basic authentication (not recommended anymore), Google will block SMTP unless you toggle this setting on.

Note: Google is phasing this out, so it’s better to use app-specific passwords with 2FA.

4. Use App Passwords with 2-Step Verification Enabled

App Passwords are the official workaround if you’ve enabled 2-Step Verification (which you should!). Here’s how to create one:

  • Visit myaccount.google.com/security
  • Scroll to “Signing in to Google” > Click App passwords
  • Generate one for your email app (e.g., “Mail App”)
  • Use that instead of your regular password in SMTP settings

It works like magic.

5. Check Gmail’s Sending Limits

Gmail has limits. If you’re sending a lot of emails in a short time (like with newsletters or bulk mail), you might hit them.

Personal Gmail limit: ~100-150 emails/day
Google Workspace limit: ~2,000 emails/day

If you exceed that, Google can temporarily block your account from sending mail via SMTP.

6. Clear Your Browser Cache and Cookies

If you’re configuring Gmail SMTP through a browser-based tool or plugin (like WordPress), your cached login or old session data might cause authentication issues. Clear it out and try again.

  • On Chrome: Settings > Privacy > Clear browsing data
  • Restart your browser

7. Use TLS or SSL Encryption (And the Right Port)

Using the wrong encryption or skipping it altogether is a major SMTP fail. Gmail requires encryption.

  • Port 465 = SSL
  • Port 587 = TLS

Don’t mix and match. Match the port to the encryption protocol.

8. Re-authenticate or Reconnect Your Gmail Account

Sometimes, your app or tool just needs a reset. Remove your Gmail account and re-add it with fresh credentials. This clears up token errors or expired sessions.

9. Use App Password Instead of Gmail Password in SMTP

Even if you think your Gmail password is right, it might be blocked due to 2FA or security filters. Generating an App Password solves 90% of Gmail SMTP login errors instantly.

10. Update Your App or Plugin

If you’re using something like:

  • WP Mail SMTP (WordPress)
  • Outlook
  • Mozilla Thunderbird
  • Zapier / Make / SendGrid integrations

Make sure the app or plugin is up to date. Gmail regularly updates its security policies, and outdated tools often fail to keep up.

How to Set Up Gmail SMTP Correctly (Step-by-Step)

For Personal Gmail Users

Here’s how to set it up manually in any app (like Outlook, Thunderbird, or WordPress):

  • Outgoing Mail (SMTP) server: smtp.gmail.com
  • Use Authentication: Yes
  • Username: yourname@gmail.com
  • Password: Gmail or App Password
  • Port: 465 (SSL) or 587 (TLS)
  • Secure connection: SSL/TLS

Save settings, send test email, done!

For Google Workspace (G Suite) Users

If you use Gmail with your custom domain (like @yourcompany.com), settings are the same—but you might need admin access to:

  • Enable SMTP relay for your account
  • Allowist the IP address
  • Generate app-specific passwords

Your admin should help set up SMTP relay if needed.

Adding Gmail SMTP to Apps Like Outlook or WordPress

Apps like Outlook, Apple Mail, or WordPress just need the correct credentials. If your emails aren’t sending from contact forms or plugins, the plugin may not be using SMTP at all. Install a dedicated SMTP plugin (like WP Mail SMTP), and configure it using Gmail SMTP settings.

Alternatives If Gmail SMTP Still Doesn’t Work

If Gmail SMTP is completely blocked or unreliable, don’t worry—there are workarounds:

1. Use a Transactional Email Service

Try a service like:

  • SendGrid
  • Mailgun
  • Postmark
  • Amazon SES

They handle bulk email sending and SMTP flawlessly—ideal for newsletters, forms, and app notifications.

2. Switch to Gmail API Instead of SMTP

The Gmail API is more reliable and secure than SMTP for heavy usage. It uses OAuth, doesn’t rely on passwords, and works well with apps. Perfect for developers and custom tools.

3. Use Google Workspace SMTP Relay (For Teams)

If you’re on Google Workspace, enable SMTP Relay from the admin console. This is more robust than basic SMTP, supports multiple users, and works well with office-wide systems.

Conclusion: Don’t Panic—Gmail SMTP Issues Are Fixable

We’ve all been there—you’re trying to send an important email through your app or website, and boom—nothing happens. Whenever you strive to accomplish a task, one obstacle or another tends to appear. When sending an email using an app or website, there can be multiple roadblocks in the form of SMTP errors and other system glitches, preventing you from completing the task.

But here’s the truth: Gmail SMTP not working isn’t the end of the world. Regardless as to what scenario we may find ourselves in, it is now easier than ever to achieve possible solutions. This ‘solution’ approach acknowledges the existence of a problem but also suggests practical strategies for resolving it. Even pending misconfiguration, outdated settings, or a security block from google, most of these issues have quick, efficient solutions. You just need to know where to look.

Start by verifying the basics—correct SMTP server, port, and credentials. Then move through the security settings: enable 2FA, use app-specific passwords, and avoid outdated plugins or apps. And if Gmail just won’t cooperate? Services like SendGrid or Google’s own API offer rock-solid alternatives.

Remember, SMTP errors are common. You’re not alone. With this guide, you now have the tools to troubleshoot confidently, reconnect quickly, and keep those emails flowing.

FAQs

1. Why is Gmail SMTP rejecting my password?

If you’ve enabled 2-Step Verification, your normal Gmail password won’t work with SMTP. You need to create an App Password in your Google account. If you haven’t enabled 2FA, check that “Allow less secure apps” is turned ON (though this option is being phased out).

2. How many emails can I send via Gmail SMTP?

For personal Gmail accounts, you can send up to 100–150 emails per day via SMTP. For Google Workspace users, the limit is around 2,000 emails per day. Going over these limits can cause Gmail to temporarily block sending access.

3. Can I use Gmail SMTP with WordPress?

Definitely. A number of WordPress users set up SMTP for contact form submissions, WooCommerce order confirmations, and newsletters. To do this, use a plugin like WP Mail SMTP, and input your Gmail SMTP settings along with an app password for proper validation

4. What’s the difference between port 465 and 587 for Gmail SMTP?

  • Port 465 uses SSL encryption.
  • Port 587 uses TLS encryption.

Both are secure, but 587 (TLS) is more widely supported and preferred for modern apps

5. Is Gmail SMTP free to use?

As noted before, Gmail SMTP is integrated at no-cost into every Gmail account including Google Workspace accounts. Remember to observe the sending restrictions to ensure your setup aligns with Google’s security requirements.

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