Why Outlook Error 3253 Occurs on Mac OS? – Reasons and Easy Fixes

Mac Outlook users have recently encountered an error code 3253, accompanied by the message, “Connection to the Outlook Server had either failed or dropped.” This error appears when trying to send an email, preventing users from sending new messages while still allowing them to receive emails. After hitting send, the email gets stuck in the Outbox with a pending status and displays the Outlook error 3253 code. The frustrating part is that this issue arises suddenly, without any warning, disrupting smooth email communication. This can seriously affect your daily workflow and business operations, making it important to resolve the error promptly.

Some Common Queries – Outlook Error 3253 on Mac OS

“I recently set up my Outlook account on my Mac, but whenever I try to send an email, I get error 3253 with a message about connection failure. Could this be due to wrong SMTP server settings? How can I verify and fix this?”

“My Outlook for Mac keeps showing error 3253 when sending emails. I noticed my Sent folder has thousands of emails. Can the large size of this folder be causing the error? What can I do to fix this?”

“After updating my Mac to the latest macOS version, Outlook started crashing and giving me error 3253 when sending emails. Could the update have affected Outlook’s functionality? How do I troubleshoot this?”

“My Outlook shows error 3253 when trying to send emails on my Mac, especially when on public Wi-Fi. Is this related to network issues? How can I fix connection problems affecting Outlook?”

“I recently reinstalled Outlook for Mac, but I’m still encountering error 3253 during email sending. Could a corrupted installation be the problem? What steps can I take to ensure a clean installation?”

Why Do Users Encounter Error 3253 on Mac Outlook?

Error 3253 usually signifies a problem with connecting to the email server. This issue can arise from several different causes. Based on investigations of multiple cases, some common reasons include:

Improper Outlook Account Setup – Error 3253 often appears when the Outlook account isn’t configured correctly on the Mac. This includes incorrect settings for outgoing (SMTP) and incoming (POP or IMAP) mail server ports, which can lead to connection failures.

Large Sent Folder Size – A frequently observed cause is an oversized Sent folder. When there are too many emails in the Sent folder, it can overload Outlook and trigger this error.

Faulty Outlook Installation– In certain cases, the error may be caused by an improper or corrupted installation of Outlook on the Mac, which affects its ability to function correctly.

How to Quickly Fix Mac Outlook Error 3253?

You can easily fix the Outlook error 3253 on Mac by following the simple methods outlined below. These steps are explained in a clear and straightforward way.

First, identify the type of Outlook account you’re using—whether it’s POP3, IMAP, or Microsoft Exchange Server. To find this information quickly, follow these steps:

• Click on File and then select Info from the dropdown menu.
• Navigate to Account Settings, and from there, choose Account Settings again from the dropdown.

Clear Mac Outlook’s Cache to Fix the Error

One effective way to resolve this Outlook issue on Mac is by resetting the cache preferences. This method often helps fix the problem. You can manually clear the unnecessary cache by following these easy steps:

1. Open the Terminal app by clicking the Spotlight Search icon (magnifying glass) located at the top-right corner of your Mac screen.
2. Type Terminal in the search bar and open the Terminal window.
3. In the Terminal, enter the command: defaults delete com.Microsoft.Outlook
   This will delete all existing Outlook preferences.
4. Next, type the command: killall cfprefsd This will clear the cached preferences.
5. After completing these steps, open Outlook and try sending an email to check if the error 3253 is resolved.

Create a New Email Account in Mac Outlook

You can also fix the issue by setting up a new email account using a fresh Outlook profile. Here’s how to do it:

1. Open Finder and locate the Outlook application.
2. Right-click on Outlook and select Show Package Contents from the menu.
3. Navigate to Contents > SharedSupport > Outlook Profile Manager and double-click to open it.
4. Click on the option to Create New Profile and enter the necessary details.
5. Click Add Account, then choose the account type (Exchange/Office 365 or POP/IMAP).
6. Enter your account information carefully and click Add Account to finish.

If you are adding an Exchange or IMAP/POP account, just follow the prompts provided during setup.

Adding an Exchange Account

Click the Add button located at the lower-left corner and select Exchange.
Enter all the necessary details to set up the Exchange account.
For automatic configuration, choose the Configure Automatically option and then click Add Account.

Adding a POP3/IMAP Account

Click the Add button and select Other Email.
Provide the required information to create and configure the account.
After filling in the details, click the Add Account option from the dropdown menu.
Finally, send a test email to verify if the error 3253 has been resolved.

Conclusion

The methods outlined above should help you fix Outlook error code 3253 on your Mac. However, if the issue persists or you continue to experience problems with your Outlook account, consider extracting your mailbox data from the Outlook OLM file. For this, a reliable third-party tool like MacArmy OLM Converter is highly recommended. This software efficiently extracts emails and other mailbox items from OLM files and saves them in PST and other formats like PDF, MBOX, EML, MSG, DOC, HTML, CSV, VCF, Office 365, Gmail, Thunderbird, Amazon Workmail, Outlook.com, Yahoo Mail, IMAP, etc. for easy access.