How to Fix Outlook Mac Error Code 3253 on Mac OS?

Mac Outlook Error Code 3253: “Connection to the Server Failed or Dropped”

Many Mac Outlook users have recently encountered Error Code 3253, which appears with the message: “Connection to the Outlook Server had either failed or dropped.” This error typically occurs when trying to send an email, causing the message to get stuck in the Outbox with a pending status while receiving emails continues to work normally.

What makes this issue frustrating is that it often happens suddenly and without warning, disrupting your ability to send emails. For professionals and businesses, this can become a serious roadblock, affecting daily communication and productivity.

That’s why it’s important to identify the cause and fix the error promptly to restore smooth email functionality.

What Causes Error Code 3253 in Mac Outlook?

Error 3253 in Mac Outlook typically points to a failed connection with the server usually while sending emails. Although the exact cause can vary from case to case, several common issues have been identified based on real user reports and troubleshooting experiences. Here are some of the most frequent reasons this issue occurs:

Incorrect Outlook Account Configuration

One of the leading causes is an improperly set up Outlook account. If the incoming (IMAP/POP) or outgoing (SMTP) server settings including port numbers are incorrect, Outlook may fail to connect to the mail server, triggering error 3253.

Overloaded Sent Folder

If your Sent folder contains a large number of emails, it can slow down Outlook’s performance and interfere with its ability to send new messages. An overloaded folder puts extra strain on the application and can contribute to connection timeouts or failures.

Improper Outlook Installation

In some cases, the error may occur due to a corrupt or incomplete installation of Outlook on your Mac. This can lead to functionality issues, including problems with sending emails or maintaining server connections.

Easy Ways to Fix Outlook for Outlook Error 3253 Quickly

You can fix Outlook Error 3253 on Mac without much hassle by using the simple methods outlined below. Each step is explained in a clear and easy-to-follow way no technical expertise required.

Before you begin, it’s important to check which type of account you’re using in Outlook whether it’s POP3, IMAP, or Microsoft Exchange. Knowing this will help you apply the correct settings and troubleshoot effectively.

Here’s how one can find out your account type:

• Run Outlook and tick on the File in the top menu.
• Select Info, then go to Account Settings.
• From the dropdown, click on Account Settings again.
• A list of your accounts will appear, showing the type (POP/IMAP/Exchange) next to each one.

Clear Outlook Cache on Mac to Resolve Error Code 3253

One effective way to fix Mac Outlook Error 3253 is by resetting Outlook’s cached preferences. In many cases, clearing the cache can restore smooth email sending and eliminate connection issues.

Follow these simple steps to delete the old cache manually:

1. Open the Terminal app

• Click the Spotlight Search (magnifying glass icon) in the top-right corner of your Mac screen.
• Type Terminal and press Enter to open it.

2. Delete Outlook preferences

• In the Terminal window, write the following command: defaults delete com.microsoft.Outlook
• Press Enter. This will remove all saved preferences for Outlook.

3. Clear cached preference data

• Now type this command in the Terminal and press Enter: killall cfprefsd
• This step removes any cached system preferences that might be interfering with Outlook.

4. Restart Outlook

• Open Outlook again and try sending a test email.
• Check if the Outlook Mac Error 3253 has been resolved.

Create a New Email Account in Outlook Using a Fresh Profile

If clearing the cache doesn’t resolve Error 3253, setting up a new Outlook profile can help. This process starts Outlook with fresh settings, which can often fix connection or sending issues.

Follow these steps to create a new email profile in Mac Outlook:

1. Find the Outlook Application

• Open Finder and locate the Microsoft Outlook app in the Applications folder.

2. Access Outlook Profile Manager

• Right-click on the Outlook app and select Show Package Contents.
• Navigate to: Contents → SharedSupport → Outlook Profile Manager
• Double-click Outlook Profile Manager to launch it.

3. Create a New Profile

• Click Create a New Profile.
• Give your profile a name and save it.

4. Add a New Email Account

• Once the new profile is created, open Outlook.
• Click Add Account, then choose the type of account you want to add for example, Exchange, Office 365, or IMAP/POP.

5. Enter Your Account Details

• Fill in the required email credentials (name, email address, password, server settings, etc.).
• Double-check the information to avoid any setup errors.
• Click Add Account to finish.

Once added, Outlook will sync with your new profile. Try sending an email to see if the Error 3253 has been resolved.

Add an Exchange or POP/IMAP Account in Outlook for Mac

Once you’ve created a new Outlook profile, you’ll need to set up your email account. Follow the instruction below based on the kind of account you’re utilizing:

Add an Exchange Account

1. In Outlook, click the Add (+) button located in the lower-left corner.
2. Choose Exchange from the list of account types.
3. Enter all the necessary account details, such as your name, email address, and password.
4. To simplify the setup, check the box for “Configure Automatically”, then click Add Account.
5. Outlook will verify your information and set up the account.

Add a POP3 or IMAP Account

1. Click the Add (+) button again, then select Other Email.
2. Fill in the required details: Email address, Password, and Incoming and outgoing mail server settings (for POP or IMAP)
3. After entering the information, click Add Account from the dropdown menu.
4. Outlook will attempt to connect and confirm the setup.

Once your account is added, send a test email to see if the Error 3253 in Outlook for Mac is resolved. If everything was entered correctly, you should now be able to send emails without any issues.

The Final Thoughts

The methods listed above should help you resolve Outlook Error Code 3253 on Mac. However, if the issue still persists or you’re unable to send emails even after troubleshooting, it’s a good idea to extract your mailbox data from the Outlook OLM file and move it to a more stable format like PST.

To do this, you can use a reliable third-party tool such as CubexSoft OLM Converter for Mac & Win OS. This software is designed to extract emails, contacts, calendars, and other mailbox items from OLM files and save them in PST or multiple other formats, making data recovery and migration hassle-free.

Alternatively, you can also use the Mac Outlook Converter another excellent choice for Mac Outlook users. It offers:

1. Multiple format support (PST, EML, PDF, MBOX, Office 365, IMAP, Thunderbird, etc.)
2. Bulk OLM file conversion to save time & effort
3. Simple and user-friendly interface, even for non-technical users
4. Full compatibility with both Windows and macOS
5. A free demo pack to try the features before purchasing

Whether you’re migrating, backing up, or recovering your Outlook mailbox, these tools ensure that your data stays safe and accessible even when Outlook isn’t functioning properly.