How to troubleshoot common email connection errors in Warmupinbox

Getting your email set up in Warmupinbox is supposed to be painless. But sometimes you hit a wall: connection errors, cryptic warnings, or your inbox just won't play nice. If you're tired of chasing your tail, this guide is for you.

I'm walking through the most common email connection errors users run into with Warmupinbox, why they happen, and—most importantly—how to fix them. Whether you're a solo founder, an agency, or just trying to warm up a new domain, this isn't rocket science. Let's get your inbox talking to Warmupinbox and move on with your day.

Step 1: Figure Out What Kind of Email Account You Have

Before you touch any settings, know what you’re working with:

  • Google Workspace/Gmail: Most common. Uses OAuth, rarely needs “app passwords.”
  • Outlook/Microsoft 365: Can be tricky—Microsoft changes their security policies a lot.
  • Custom domain with IMAP/SMTP: Anything not Google or Microsoft. Think Zoho, private servers, or webmail.

Why it matters: Each provider has its own quirks. Most connection errors come from mismatched settings or missing permissions.

Pro tip: Don’t guess. Log into your email’s web portal and check who hosts your mail.

Step 2: Read the Error Message—Don’t Just Click Away

Warmupinbox tries to tell you what’s wrong. Even if the error looks like gibberish, copy-paste it somewhere. Here’s a quick decoder:

  • “Authentication failed” or “Invalid credentials”: Your login details are wrong, or you need an app password.
  • “IMAP/SMTP server not found”: The server address is off, or DNS hasn't propagated.
  • “OAuth error”: Permissions weren’t granted, or your session expired.
  • “App not authorized”: Your email provider is blocking the connection—usually a Microsoft or Google thing.

If it’s generic (“connection error”), that usually means the server rejected the login or the port is blocked.

Step 3: Double-Check Your Email Settings

This is the most common place people mess up. Here’s what to look for, broken down by provider.

Google Workspace or Gmail

  • Don’t use your regular password. Use OAuth (the “Sign in with Google” button).
  • If that fails, you might need to enable 2-Step Verification and create an App Password.
  • Make sure IMAP is enabled:
  • Go to Gmail > Settings > See all settings > Forwarding and POP/IMAP > Enable IMAP.

What doesn’t work: Trying to use your Gmail password with IMAP/SMTP if 2FA is on. Google blocks that.

Outlook / Microsoft 365

  • Use the “Sign in with Microsoft” option if available.
  • If you get “app not authorized,” you might need your admin to approve Warmupinbox in your Azure portal.
  • For older accounts, sometimes you need an App Password.
  • Make sure IMAP and SMTP are enabled in your account settings.
  • Some tenants block external connections—ask your IT admin.

What doesn’t work: Outlook.com personal accounts often don’t allow IMAP/SMTP connections by default. Don’t expect miracles.

Custom Domain (IMAP/SMTP)

  • Double-check your IMAP and SMTP server addresses. Sometimes it’s mail.yourdomain.com, sometimes it’s imap.yourhost.com.
  • Use the correct ports:
  • IMAP: usually 993 (SSL)
  • SMTP: usually 465 (SSL) or 587 (TLS)
  • Make sure your email account actually allows IMAP/SMTP. Some cheap hosting disables this by default.

What doesn’t work: Guessing ports or copying from another domain. Always check your host’s documentation.

Step 4: Fix Security Permissions (This Trips Up Everyone)

Most connection errors aren’t about typos—they’re about security. Here’s how to cut through the noise:

  • OAuth not working? Make sure you grant all permissions Warmupinbox asks for—even if it feels like a lot.
  • Admin controls: If you’re on a business account, your admin might need to “whitelist” Warmupinbox or allow third-party apps.
  • App Passwords: If two-factor authentication is on, you usually need an app password for IMAP/SMTP.
  • Unusual location or login attempt: Sometimes, your provider blocks logins from new locations. Check your email for “suspicious login attempt” warnings and approve them.

Pro tip: If you’re stuck, try logging in from a different browser or incognito mode. Sometimes a stale session messes up OAuth.

Step 5: Check for Firewall or Network Issues

If you’re working from an office, co-working space, or behind a VPN, outgoing ports might be blocked.

  • IMAP (993) and SMTP (465/587) need to be open.
  • Try connecting from your phone’s hotspot—if it works, your network’s blocking the connection.
  • Some hosts (like GoDaddy, Bluehost) block outbound SMTP to prevent spam. If so, you’ll need to talk to their support or use a different provider.

Step 6: Common Pitfalls and What to Ignore

Here’s what actually matters—and what’s a waste of time:

What to Ignore

  • Changing DNS records: Unless you just set up the domain, this won’t help connection errors.
  • Resetting your password over and over: If you’re using OAuth or app passwords, regular password resets don’t help.
  • Messing with SPF/DKIM: Important for deliverability, but irrelevant for connecting your inbox.

What to Watch Out For

  • Inbox limits: Some providers throttle connections. If you’ve tried and failed a dozen times in a row, wait 15–30 minutes.
  • Suspicious logins: Too many failed attempts can trigger account locks.
  • Expired app passwords: Microsoft and Google sometimes quietly expire these—regenerate if nothing else works.

Step 7: When to Contact Support (And What Info to Give)

If you’ve made it this far and it’s still not working, don’t just say “it’s broken” when you reach out. Here’s what to include:

  • The exact error message (copy-paste is your friend).
  • What type of email account you’re using (Gmail, Outlook, custom).
  • Whether you’re using OAuth or app password.
  • Anything you already tried, so support doesn’t ask you to do it again.

Pro tip: Screenshot your settings page (blur out passwords) and attach it.

Step 8: Keep It Simple and Iterate

Don’t overthink this. Ninety percent of email connection problems in Warmupinbox boil down to:

  • Wrong login method (password vs. OAuth vs. app password)
  • Missing permissions or admin blocks
  • IMAP/SMTP disabled or wrong server info

Test one thing at a time, don’t make five changes before checking if it works, and don’t be afraid to start over with a fresh connection.

If you’re stuck, take a breath. Even the pros get tripped up by email authentication. Iterate, double-check, and you’ll get there—no need to smash your keyboard.