Key takeaways
- Queued emails wait in line to send due to connectivity, storage, or platform limits
- Most queued emails resolve automatically within 15 to 30 minutes
- Battery optimization on Android is the most common mobile cause
- Gmail free accounts allow 500 emails per day; Google Workspace allows 2,000
- Large attachments over 25 MB can cause immediate queuing
If you have ever sent an email only to discover it was stuck as "queued," you know the frustration of wondering, "Why is my email queuing?" With 361.6 billion emails sent daily worldwide, email remains essential for professional communication. Yet queued messages continue to frustrate busy professionals who rely on timely delivery.
Whether you use Gmail, Outlook, or another email client, queued emails can occur for many reasons. Whatever the cause, a queued email is waiting to be sent until the issue preventing its delivery is resolved. In this article, we will explain what a queued email is, why it happens, and how to fix it.
What is a queued email?
A queued email is a message that has been accepted by your email system but is waiting in line to be sent. The message has not left your device yet. Typical causes include connectivity issues, server pacing, or temporary delays. In most cases, queued emails resolve automatically within 15 to 30 minutes. However, if your email remains queued for more than 2 hours or shows a failed status, you should troubleshoot immediately by checking your internet connection, restarting your email application, and verifying that you have not exceeded your platform's daily sending limits.
Understanding how "queued" differs from other email statuses helps you decide whether to wait or act immediately:
- Outbox is the temporary holding folder where emails sit after you click "Send" but before transmission. "Outbox" refers to the visible folder location, while "queued" describes the system status. Both indicate your email is waiting to be sent.
- Pending means your email is actively being transmitted or awaiting delivery confirmation from the receiving server. Unlike queued emails, pending messages have already begun the sending process but have not yet received acknowledgment of delivery.
- Failed means the sending attempt was unsuccessful, and your email was not delivered. Failed emails require immediate attention, as you will need to check the error message and take corrective action.
Why is my email queued?
Emails can be queued for various reasons, and often these issues have nothing to do with you. For example, an email client might be experiencing a technical issue that they will resolve themselves.
If you have noticed an accumulation of queued emails or a message has been waiting longer than usual, it may be worth diagnosing the issue yourself.
Common causes of queued emails
Here are the most frequent reasons your emails might be getting stuck:
- Internet connectivity problems (most common; affects all platforms equally)
- Mobile app battery optimization (especially on Android; overrides sync settings)
- Large attachments exceeding size limits (25 MB typical maximum)
- Account sync or authentication problems (especially OAuth token expiration on Mac)
- Exceeded daily sending limits (Gmail: 2,000/day for Workspace; Outlook: 10,000 recipients/day)
- Storage capacity reached (mailbox quota exceeded)
- Offline mode accidentally enabled (Outlook-specific)
- Outdated email app versions (causes sync and authentication failures)
How to fix queued email issues
Emails stuck in a queue for an extended period may require your intervention. Luckily, identifying these issues without technical knowledge is quick and easy.
1. Check your internet connection
One of the most common reasons for a queued email is a lack of internet connection. Before resetting your network equipment, try these platform-specific fixes:
- Android: Check if battery optimization is blocking your email app (Settings > Apps > [Email App] > Battery > change to "Unrestricted")
- iOS: Verify Push is enabled in Settings > Mail > Accounts > Fetch New Data
- Mac: Consider regenerating an app-specific password if you are repeatedly prompted for your password
If you have confirmed these settings are correct and you are still experiencing issues, test other devices on the same network. If multiple devices are struggling, reset your modem and router or contact your service provider.
If your device is connected to a cellular network, wait 15 to 30 minutes for queued emails to send automatically before taking action. If emails remain stuck after this period, restarting your email application is often more effective than a full device restart.
2. Check for offline mode
Some email clients, like Outlook, include an offline mode that can trick you into thinking you can send messages when your connection drops. Emails composed in offline mode will not send until you reconnect and switch back to online mode.
If your email shows "Queued" or "Pending" status, wait 15 to 30 minutes before troubleshooting. However, if the email remains stuck after 2 hours or shows "Failed" status, take action immediately.
For Outlook: Check the bottom-right status bar for a "Working Offline" indicator. If you see it, click the Send/Receive tab and toggle the Work Offline button to go back online.
3. Manage your sending limits
Both free and paid email accounts have sending limits that protect platform infrastructure and prevent spam.
If you are hitting your daily email limit, consider scheduling your messages and spacing them out. This can be done through both Gmail and Outlook accounts. For even smarter delivery, tools like Superhuman Mail can help you send at the right time based on when recipients are most active.
4. Free up storage space
If your Gmail account is approaching its 15 GB storage limit (shared across Gmail, Drive, and Photos) or your Outlook mailbox is near capacity, you will need to free up space before queued emails can send.
To free up space quickly, delete large emails with attachments from your Inbox and sent folder. For Gmail, search by size using "has:attachment larger:5MB" to quickly identify oversized messages. In Outlook, enable auto-archiving to automatically move older messages to an archive mailbox. Clear the trash folder to permanently remove emails from your storage quota. Once you have freed up space (aim for 10 to 15% buffer), queued emails should begin processing automatically.
5. Reduce attachment size
Large attachments are a leading cause of queued emails that many people overlook. Both Gmail and Outlook have a 25 MB attachment limit per message.
How to handle large files:
- Gmail: Use Google Drive sharing instead of attachments for files over 25 MB
- Outlook: Use OneDrive or compress files before attaching
- Apple Mail: Enable Mail Drop to automatically upload large files to iCloud (handles files up to 5 GB)
6. Update your email client app
If you are using a phone to access your email, the problem may be a configuration issue rather than an outdated app.
On Android, aggressive battery optimization restricts your email app's background activity. On iOS, check that Push notifications are enabled in Settings > Mail > Accounts > Fetch New Data. On both platforms, verify your phone storage is not full, as this prevents emails from processing.
To check if your app runs the latest version, open your device's app store and search for your email client. If there is an option to update, download the newest version, then send a test message to verify emails now send successfully.
7. Clear app cache
Corrupted cache can cause persistent bugs where deleted emails continue to appear in your outbox or keep attempting to resend.
On Android, go to Settings > Apps > [Your Email App] > Storage and tap "Clear Cache." If issues persist, tap "Clear Data" (note: you will need to re-add your account). On iOS, you may need to delete and reinstall the email app to clear cached data.
8. Verify authentication settings
Account sync or authentication problems can cause emails to queue even when your internet connection is strong. This is especially common on Mac devices where OAuth tokens expire but Mail does not refresh them properly.
To fix this, generate an app-specific password from your Apple ID account page, remove your existing email account from Mail, and re-add the account using the app-specific password. For other platforms, try signing out of your email account and signing back in to refresh your authentication credentials.
Why is my email queuing on my phone?
Mobile devices have additional factors that can cause queuing beyond what desktop users experience.
Android fixes
Battery optimization blocking is the most common Android queuing issue. Android devices, particularly Samsung phones, aggressively restrict email app background activity.
How to fix (Samsung devices):
- Go to Settings > Apps > [Email App] > Battery
- Change from "Restricted" to "Unrestricted"
- Disable "Put app to sleep" and "Deep sleeping apps"
Alternative quick fix: Turn ON Airplane mode, delete or modify the stuck email in your outbox, then turn OFF Airplane mode. This resets your network connection without requiring a full device restart.
Why is my email queuing on iPhone?
- Enable Push notifications: Disabled Push settings can delay email synchronization on iOS devices. Go to Settings > Mail > Accounts > Fetch New Data and enable Push for your email accounts.
- Check iCloud storage: A full iCloud storage account can prevent emails from sending. Go to Settings > [Your Name] > iCloud > Manage Storage and free up space or upgrade your plan.
- Verify outgoing server settings: Sometimes iOS syncs with an incorrect outgoing mail server. Go to Settings > Mail > Accounts > [Your Account], tap on Outgoing Mail Server, and select the correct server from the dropdown menu.
Desktop fixes for queued emails
Mac fixes
OAuth token expiration: Authentication tokens can expire but Mail does not refresh them properly, causing emails to queue despite correct credentials. Symptoms include emails queueing and Mail repeatedly asking for your password.
To fix this, generate an app-specific password from your Apple ID account page, remove your existing email account from Mail, and re-add the account using the app-specific password.
Check outgoing server assignment: If you have multiple email accounts, the wrong SMTP server might be assigned to outgoing messages. Open Mail > Settings > Accounts > [Your Account] > Server Settings and verify the "Outgoing Mail Server (SMTP)" dropdown shows the correct server.
Windows and Outlook fixes
Toggle offline mode: Outlook sometimes enters offline mode when your connection drops and does not automatically return online. Check the bottom-right status bar for "Working Offline" indicator. If offline mode is active, click Send/Receive tab > Work Offline button to toggle back online.
Edit stuck emails with large attachments: If an email with a large attachment is stuck in your Outbox, go to File > Work Offline, navigate to your Outbox, open the stuck email and remove or reduce the attachment, move the email to your Drafts folder, toggle back online, and resend with a smaller attachment.
Increase server timeout: If emails are stuck despite good connectivity, the server connection may be timing out. Go to File > Account Settings > Account Settings, select your account > Change > More Settings, and in the Advanced tab, increase timeout from 30 to 60 seconds.
Understanding email error codes
When you receive an error message with your queued email, the error code tells you whether to wait or take immediate action. 4xx error codes indicate temporary issues that usually resolve automatically, while 5xx codes signal permanent problems requiring immediate attention.
4xx codes: Temporary issues
Email errors starting with "4" indicate temporary delivery problems that typically resolve automatically:
- 450 4.2.1: Recipient's server is rate-limiting. Wait and retry later.
- 452 4.2.2: Recipient's inbox is out of storage. Contact them to free up space.
- 451 4.3.0: Temporary server rejection. The system will automatically retry.
- 421 4.3.0 / 421 4.7.0: Connection expired due to network issues. Try again in a few minutes.
5xx codes: Permanent issues
These codes require your intervention:
- 550 5.1.1: Mailbox unavailable or rejected as spam. Verify the recipient's email address is correct.
- 553: Mailbox name does not exist. Double-check the email address for typos.
Quick decision guide: Wait 15 to 30 minutes if you see queued status, pending status, or 4xx error codes. Act immediately if you see failed status, 5xx error codes, or emails stuck longer than 2 hours.
How to prevent email queuing issues
Taking proactive steps can help you avoid queued emails in the first place.
- Know your platform limits. Track your daily email volume and stay well below your limits. Gmail blocks sending for 24 hours when you exceed limits. Microsoft 365's 30 messages per minute rate limit can trigger queuing even below daily caps.
- Use cloud sharing for large files. Instead of attaching large files directly, share via Google Drive for Gmail, OneDrive for Outlook, or Mail Drop for Apple Mail.
- Monitor your inbox regularly. Check your Outbox before ending your workday to verify no emails are stuck. Review bounce notifications weekly and remove hard-bouncing addresses immediately. You can also set up email filters to better organize incoming messages and keep your inbox clean.
- Keep your email app updated. Outdated apps are a common source of sync and authentication failures. Enable auto-updates for your email client to avoid issues. If you notice recurring bugs, try clearing your inbox to reduce the load on your email app.
- Use a reliable email client. Consider using Superhuman Mail, which is optimized for speed and reliability. Superhuman Mail works with both Gmail and Outlook, offering features like Smart Send to deliver messages at the optimal time and Read Statuses to confirm delivery. If you have ever sent an email by mistake, Superhuman Mail also offers an extended undo send window for added peace of mind.
Fix your queued emails and send with confidence
Now that you understand why your email is queuing and how to fix it, you can get back to work on the things that matter most. The most common causes are internet connectivity issues, battery optimization on mobile devices, large attachments, and exceeded sending limits. Most queued emails resolve automatically within 15 to 30 minutes.
If you are tired of dealing with email queuing issues and want a faster, more reliable email experience, Superhuman Mail helps you fly through your inbox twice as fast and is designed for busy professionals who cannot afford delivery delays. With features built for inbox zero and seamless Gmail and Outlook integration, Superhuman Mail ensures your messages send when they should. Try Superhuman Mail today.
FAQs
How do I fix a queued email?
First, check your internet connection and verify your email app is not in offline mode. If the email remains stuck, clear your app cache, reduce attachment size if over 25 MB, and ensure you have not exceeded platform sending limits. On Android, disable battery optimization for your email app in Settings > Apps > [Email App] > Battery.
Why are my emails stuck in the queue?
Emails get stuck in the queue due to connectivity issues, large attachments exceeding 25 MB, exceeded daily sending limits, full storage, or battery optimization settings blocking your email app. On mobile devices, battery optimization is the most common cause, especially on Samsung phones.
Will queued email be sent automatically?
Yes, in most cases. Once you regain internet connectivity or the temporary server issue resolves, your email client will automatically attempt to send queued messages. Most queued emails send within 15 to 30 minutes once the underlying issue resolves.
What does it mean on Gmail when it says queued?
When Gmail shows "queued," your email has been accepted but is waiting in line to be sent. The message has not left your device yet. This typically happens due to poor connectivity, sync issues, or sending limit restrictions. Queued emails in Gmail usually resolve automatically once the issue clears. For more Gmail tips, see our complete guide.
How long does it take for a queued email to send?
Most queued emails send automatically within 15 to 30 minutes once the underlying issue resolves. If an email remains queued for more than 2 hours, it likely requires manual intervention such as checking your connection, clearing cache, or reducing attachment size.
