(Fixed) Microsoft Outlook Emails Stuck in Outbox | 8 Ways

You will learn the possible reasons and 8 solutions to Microsoft Outlook emails stuck in Outbox. And it is also suggested to backup Outlook emails to keep them safe.


By Ivy Updated on February 24, 2023

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Why Are Outlook Emails Stuck in Outbox?

Dealing with Microsoft Outlook emails stuck in outbox is frustrating, especially when you don’t know why it happens. Here we summarize all the possible reasons in the following:

  • Large attachment.
  • Incorrect Send and receive settings.
  • Email is opened or viewed in Outbox. This is caused by a number of Outlook add-ins, such as Business Contact Manager (BCM), Social Connector add-in, Xobni, iTunes Outlook Addin, iCoud add-in, etc.
  • Wrong password for the email account.
  • Your Outlook or mail server is offline. For example, your Exchange email account is configured to use cached exchange mode or you configure the LoadTransportProviders registry key in Outlook 2007, 2010 and 2013.
  • No default email account.
  • Outlook is in use with another program. For example, users are trying to access Outlook data files.
  • Email authentication settings.
  • Antivirus or antispam software is scanning outgoing emails.

How to Fix Outlook Emails Stuck in Outbox

After learning the possible reasons, you can try to fix emails stuck in outbox Outlook 2016, 2019, 2021, 2022 or previous version. The first thing is to be sure the Outlook or mail server is online.

  • If it is offline, you will see the “Disconnected” or “Trying to Connect” status.


  • For on-premise Exchange server, you need to contact your admin.
  • For Offline 365, you need to check your internet connection and wait a few minutes.

After making your Outlook or email server online, if you still have this problem, please continue to see below. Here are 8 effective methods for Outlook emails stuck in outbox not sending.

Way 1: Remove the Large Attachment

If your email contains a large attachment, it may be the cause of emails stuck in outbox but have sent. You need to remove this attachment and resend the email.

1. Click Send/Receive > Work Offline. Then, in the navigation pane, click Outbox.

Work Offline

2. Drag the message to the drafts folder. Double-click to open the message, click the attachment and press Delete.

Drag Stuck Message

Note: You may receive an error message saying "Outlook has already begun transmitting this message", close Outlook and then repeat the steps to delete the attachment.

3. After deleting the attachment, click Send/Receive > Work Offline to resume working online.

Tip: You still can delete the email message to resolve the “Outlook Emails Stuck in Outbox” issue.

Way 2: Enable Send immediately when connected option 

In Outlook 2010 and later versions, such as, 2016, 2019, 2021, 2022:

1. Click File > Options.

2. It will open an Outlook Options dialog box. Click Advanced.

3. Scroll down to Send and receive section and check Send immediately when connected. Then, click OK.

Send Immediately

In Outlook 2007 and 2003

1. Click Tools > Options.

2. It will open the Options dialog box. Click Mail Setup.

3. Scroll down to Send and receive section and check Send immediately when connected. Then, click OK.

Way 3: Resend Open or Viewed Email

If you open or view the Outlook message waiting to be sent, it will be marked as read, and not go. At the same time, the title of the message will not display in bold.

To resolve this stuck issue, you can choose to uninstall or disable Outlook add-ins affecting the sending process. But it’s definitely not the best way. Because you need to rely on some of them to complete your work.

If you are in such a case, drag the stuck message to another folder, such as drafts, open the email in that folder, and click the Send button.

Send Stuck Message

Way 4: Change Password in Outlook

If you recently change the password of your mail account such as Gmail or Outlook.com, you need to update this in Outlook. Otherwise you may encounter Outlook emails stuck in outbox or emails stuck in Outbox Gmail issue.

1. Open Outlook Accounts Settings.

  • In Outlook 2010 and later, click File > Info and select Account Settings twice.

Account Settings

  • In Outlook 2007, click Tools > Account Settings > Email.
  • In Outlook 2003 and earlier, click Tools > E-mail accounts > View or Change existing accounts.

2. In the Account Settings window, select the account with the wrong password and click the Change ... button.

Change Password

3. Under the Logon Information, type your new password in the Password box. Then, click Next > Finish.

Way 5: Delete LoadTransportProviders in Registry

If you configure the LoadTransportProviders register key, you may also receive the outlook message stuck in outbox issue. Delete it and then send the hanging email.

Warning: Modifying the registry may cause serious problems, which may require you to reinstall Windows. So please backup system before you make any changes.

1. Start Registry Editor. Locate the following key:


Note: The x.0 in the registry key refers to the Outlook version. 15.0 = Outlook 2013, 14.0 = Outlook 2010, 12.0 = Outlook 2007.

2. Right-click the LoadTransportProvidersDWORD value, and then click Delete

Way 6: Restart Outlook in Safe Mode

1. Hold down the Ctrl button and double-click the Outlook shortcut.

2. Keep holding down the Ctrl button until you are asked to start Outlook in safe mode. Click Yes to continue.


Way 7: Set a Default Account

1. Open the Account settings window. If you don’t know the method, refer to step 1 in Way 4.

2. Click the E-mail tab and check the default account. It will display a message like “send from this account by default”.

3. If none of your email accounts is set as default, select the account you expect and click the Set as Default option.

Set as Default

Way 8: Check Email Server Authentication

1. Open the Account settings window. Double-click the account and click Tools > Account Settings > Email.

2. Switch to the Outgoing Server tab and make sure the recommended settings are checked. Some providers require a password but few require secure password authentication, so don’t check it unless your mail server explicitly requires it.

Outgoing Server

3. Go to the Advanced tab and check if the Outgoing server port number is correct.

★ SMTP accounts usually use port 25 or 587. The encrypted connection (SSL) of it is on TCP port 465.


★ POP accounts usually run on port 110. If you use Gmail as a POP account, enter 995 on the "Incoming server (POP3)" field and 465 on the "Outgoing server (SMTP)" field. Select the option "This server requires an encrypted connection (SSL)" .

★ IMAP email accounts use port 143. If you use Gmail as an IMAP account, enter 993 on the "Incoming server (POP3)" field and 587 on "Outgoing server (SMTP)". Check the box "This server requires an encrypted connection (SSL)" .

Backup Outlook Emails to Keep It Always Safe

Your email messages are valuable, if it is mistakenly deleted or damaged, you will lose them completely. To ensure you always have complete access to them, it’s suggested to backup Outlook emails to make a duplicate copy. The best Outlook backup software - AOMEI Backupper Professional can help you.

It offers you the Outlook Backup feature to backup any data on it, such as emails, attachments, calendars, contacts, etc.
It is able to run Outlook email backup automatically with the Schedule Backup feature. By default, it will backup only changed files in a scheduled task.
It allows you to backup Outlook emails to external hard drive, USB drive, network or NAS devices, cloud drive, etc.

Please download this powerful backup software to have a try! For server users, try AOMEI Backupper Server.

Download Free TrialWin 11/10/8.1/8/7/XP
Secure Download

Step 1. Open Outlook, and be sure you log in with the account containing messages you want to backup.

Step 2. Launch AOMEI Backupper Professional and click Backup and Outlook Backup.

Outlook Backup

Step 3. Click Add Outlook data and select the account containing email messages you want to backup. Then click OK.

Add Outlook Data

Step 4. Click the second box to select a local path, network or NAS location, or cloud drive to store your Outlook emails.

Select Destination

Step 5. Enable “Daily”, “Weekly”, “Monthly” or “Event triggers ” schedule backup and click Start Backup to backup Outlook emails automatically.

Schedule Backup


  • By default, if you enable schedule backup, this software will use “Incremental Backup” to backup only changed files. You can change it to “Differential Backup” as well.
  • If you are worried about the backup disk full issues, the best way is to enable automatic backup cleanup methods in Backup Scheme. It will delete old backup images automatically based on the selected method.


This article illustrates all the possible reasons and 8 effective methods to fix Outlook emails stuck in outbox. If you are in this problem, please check the reasons to find the root cause first.

Besides, it’s necessary to backup Outlook emails if you don’t want to lose any of your important data in it. To include the newly added emails, the best way is to run Outlook backup automatically. And it also helps to backup PST files to OneDrive.

Ivy · Editor
Ivy is an editor of AOMEI Technology, she covers backup & restore,hard disk & partitions management and cloud files transfer and so on for AOMEI. She is an outgoing girl and enjoys helping people find solutions to their problems. She loves traveling, eating, reading and so on. She usually hangs out with friends at her leisure time.