Check How to Fix Outlook for Mac Error Code 3253!

admin | how to Outlook outlook for mac | 4 minutes read | Modified on: 18-07-2026

Microsoft Outlook for Mac is an essential e-mail client for many business people due to its ability to integrate e-mails, calendar, and tasks seamlessly . However, problems with synchronization may interrupt users workflow. The most popular problem among all the issues that occur is Error Code 3253.

Whenever this error happens, a user will get the following message: “Connection to the server failed or was dropped.” In simple terms, it means that Microsoft Outlook is attempting to send an e-mail while the connection to the outgoing mail server (SMTP) has timed out or terminated.

Do not be scared if your outbox stops working. This guide will teach you how to solve Error Code 3253.

What Causes Outlook Error 3253?

It will be useful to take some time to explore the cause of the problem before exploring the solutions. There is however just one reason why error 3253 is occurring. In most cases, this occurs due to:

  • Corrupt Outbox Items: A huge file attachment or corrupted email that is stuck in the Outbox.
  • Server Configuration Issues: Incorrect SSL configuration or wrong SMTP port number.
  • Loss of Network Stability: Loss of internet connection while transferring data.
  • Corrupt User Account Profile: Issue in the account profile cache.

Step-by-Step Solutions to Fix Error 3253

Follow this process to solve the problem.

Step 1. Clean the Outbox Folder

Error 3253 usually occurs when a problematic email gets stucked in the Outbox. The sending of corrupted or oversized files by Outlook results in a timeout error.

Step 2. Launch Microsoft Outlook on your Mac.

Step 3. Go to the left pane and check the Outbox folder in your account.

Step 4. Any email found in this location must be deleted (or moved to the Drafts folder).

Step 4. Go to the Send/Receive tab and hit Sync Now button to see if it works.

2. Verify and Reconfigure SMTP Server Settings

If your Outbox is clean but still experiencing an error, then there is an issue in the handshake process that Outlook does with your email provider’s outgoing server. It’s time to check your Port and SSL settings.

  1. In Outlook, click on Tools menu located at the top of your screen and choose Accounts.
  2. Choose your problematic email account from the left panel.
  3. Move on to the Outgoing Server (SMTP) part.
  4. Make sure that your server name is correct; contact your email service provider for confirmation (smtp.gmail.com for Gmail, smtp.mail.yahoo.com for Yahoo).
  5. Port number should be either 465 or 587.
  6. Check the Use SSL to connect (Recommended) option.
  7. Click on Advanced… and make sure that your authentication settings match those of your incoming server.

3. Create a New Outlook Profile

If the server settings are right, it is possible that your existing Outlook profile, which used to be called identity, may have been damaged. A new profile creation will reset the local database settings of the application without affecting the server data.

Step 1. Close Outlook Completely: Ensure the app is not running in the background.

Press Command + Q to shut down Outlook entirely.

Step 2. Open Finder and Locate the App:

Open Finder, navigate to your Applications folder, right-click (or Control-click) on Microsoft Outlook, and select Show Package Contents.

Step 3. Launch the Profile Manager:

Navigate through Contents > SharedSupport and double-click on Outlook Profile Manager.

Step 4. Create a New Profile:

Click the plus (+) button at the bottom of the window and type a name for your new profile (e.g., “Fresh Start”).

Step 5. Set as Default:

Select the newly created profile, click the gear icon at the bottom, and choose Set as Default.

Step 6. Restart Outlook:

Close the Profile Manager, launch Outlook, and re-add your email account.

4. Toggle the “New Outlook” Interface

Microsoft provides two separate architectures for macOS, which are the “Legacy Outlook” and “New Outlook”. Sometimes a flaw that is specific to only one version causes the appearance of Error 3253.

  • If you are using New Outlook: Go to the menu bar at the top left, and then uncheck New Outlook to move to the legacy architecture.
  • If you are using Legacy Outlook: Go to the menu bar and click the toggle button to enable New Outlook.

Allow the application to sync and check if the transmission error is resolved.

Use Professional Simple Approach to Backup OLM files

Although the above manual troubleshooting methods solve the problem at its core in 90% of the cases, there are situations in which local corruption of the database has reached such proportions that the Outlook application will not even load, synchronize, or allow you to view your archive. In case you have found yourself in an endless cycle of problems or have to migrate your data urgently due to total instability of Outlook,

it is time to take measures.

Why Use MacMister OLM Converter?

In case you get stuck with Outlook for Mac application, all your local files will be kept safe in a .olm file format. MacMister OLM Converter for Mac & Windows is enterprise-level extraction software created for macOS platform users. In case of Error 3253 and database corruption, this tool will help you extract and convert your files with ease.

  • The tool easily transforms the non-accessible OLM file to commonly used MBOX, PST, EML, PDF, and HTML file format.
  • You can skip desktop applications and directly migrate your OLM file data to your preferred cloud-based mail clients such as Apple Mail, Gmail, Office 365, and Yahoo Mail.
  • The application ensures that your data folder structure, email reading status, and attachments are intact after conversion.
  • It comes with a very easy-to-use and native macOS user interface and makes multiple OLM file conversions in no time.

If manual fixes leave you stranded, downloading the MacMister utility ensures you never lose a single byte of your email history due to Outlook server errors.