This document explains how to fix Microsoft Outlook error 0x800042109 if it is not working properly or throwing an error while installing, updating,  launching/opening, performing action like sending or receiving emails, configuring emails etc.

The error may look like:
Service reported error (0x800042109) Outlook cannot connect to your (smtp) e-mail server.

This solutions applies for following version of Microsoft Outlook:

  • Outlook 2007
  • Outlook 2010
  • Outlook 2013
  • Outlook 365
  • Outlook 2016
  • Microsoft Office (2013/365/2016)
Error InformationError Descripton
Error 0x800042109 Outlook Overview
0x800042109 Error Code Log
Avg. Time to Resolve Issue   50 mins
Difficulty Very Hard
Log Name: Microsoft Outlook <version> 7.43
Source: Mail size Conflict
Event ID: 4861
Operating System
  • Windows 7
  • Windows 8
  • Windows 10
Level: Application Level
User: <Outlook username>
Description:
  • Faulting Application Name: Microsoft Outlook <Application name>, version: 8.4.2479.21130, time stamp: 0×15752145
  • Faulting module name: Outlook  error.dll, version: 8.0.9011.82425
  • Exception code: 0xa03e751g
  • Fault offset: 0xc08b864b
  • Faulting process ID: 0×205
  • Faulting application start time: 0x05bace7a90818514
  • Faulting application path: ~<userpath>
  • Faulting module path: ~C:\Program Files (x86)\Microsoft Outlook\<appname>
  • Report ID: a4b72f67-5623-51d5-4877-9355bbg2e167

Cause of 0x800042109 Outlook Error Code

  • ISP Port block
  • SSL resolving issue
  • Corrupt Outlook core files

How to Resolve Outlook Error Code 0x800042109

Step 1: Check Proxy Server Settings
1. Press Windows Key + R. Run Dialogue Box will open up.
2. Type CMD and Press OK.
Office Resolve Error Proxy Check 3. In command Prompt Copy following commands (Simply select the command and press ctrl+c and press ctrl+v in command prompt)

 netsh winhttp show proxy 

Check Proxy Setting

Note: You will need Administrator Access to Run the above command. Simply Right Click on CMD button and select “Run as Administrator

If you get the message “Direct Access (no proxy server)“, continue to the next step otherwise disable proxy from Network Settings.

 You can contact our 24×7 Live support for any help during the whole process. 

Step 2: Temporarily Disable Windows Firewall Setting :
1. Press Win Key + R and Type “Firewall.cpl” (without quotes)
2. Click OK.

3. Click on “Turn Windows Firewall On or Off
Turn Windows Firewall on or off4. In Private network Setting, select “Turn off Windows firewall (not recommended)
5. Do the same for Public Network Setting.
Disable Windows Firewall6. Press OK.
Note: After the issue is resolved you must turn the Windows Firewall on.

In most cases Outlook error code 0x800042109 should be resolved by following above steps. If however the issue still persists it means there is some critical issue with your system which needs to be fixed manually and is recommended to be done by an experienced Computer Technician.

You can chat one-on-one with one of our Outlook Support Representative 24/7 by clicking on the Chat button.

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Last Updated: 07/02/2016
Solution ID: 603612

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