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Microsoft Exchange - OWA - MFA

This document explains how to implement Monosign with Microsoft Exchange - OWA.

📑 Instructions

This documentation contains 4 main steps for integration.

  1. Creating an Application on Monosign

  2. Configuration Single Sign-On for Microsoft Exchange - OWA

  3. Assign a user to the Microsoft Exchange - OWA app

  4. Sign In Test

1- Creating an Application on Monosign

Create your application on Monosign and configure your access policy. Once you create, click “Keys” and add a new Access Key for Rest API Key for access.

We will need this information while configuring the Microsoft Exchange - OWA app.

Your application needs to have access to groups. If you are configured it yet, you can Edit your application, go to the “Source, Provider and Profile” tab, and configure User Group Access Type “Assigned Users and Defined Sources”. It means this application can access users’ groups when they sign in.




User Access Type

Defines which Users will access to this application.

Only Assigned Users
All Users

User Group Access Type

Defines application’s user group access

Only Assigned Users
Assigned Users and Defined Sources
All Users

Profile Access Type

Defines Application’s user’s profile access

Restricted - Only restricted user profile attributes
All - All user profile attributes

2- Configure your OWA App on IIS

2.1- Install IIS Module Files

Monosign MFA for Exchange OWA is working with IIS customization. Before continue please download below zip file.

⬇️ Download the latest IIS Module.

Zip file is contains below files.

Copy the IIS Module “dll” files under your application “bin” folder.

IIS Module files

For OWA use below path.

C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa\bin

Please create bin directory if does not exist.

2.2- Configure OWA

Connect your OWA server and open IIS (Run inetmgr.exe).

Expand your Computer Name and click Sites then double-click “Default Web Site” right-click “owa” and click “Explore”. You will be redirected to the Explorer window that contains OWA configuration files.

Back up your web.config file just in case.

Right-click on web.config and Open with Notepad.

Edit and put your settings between the appSettings section.

<add key="MONOSIGN_API_URL" value="https://your-api-url/"/>
<add key="MONOSIGN_API_KEY" value="your-api-key"/>
<add key="MONOSIGN_API_SECRET" value="your-api-secret"/>
<add key="MONOSIGN_DEBUG_MODE" value="true"/>
<add key="MONOSIGN_LOG_PATH" value="log-directory"/>
<add key="MONOSIGN_USER_EXCEPTIONS" value="if-you-have-type-email@address"/>

For example;

Add the following line to the end of the system.webServer/modules section.

<add name="MonoSignExchange" type="MonoSign.IISModule.MSExchange, MonoSign.IISModule"/>

For example;

Save the file. It will take a couple of minutes to restart the app.

Multiple User Sources on Monosign (Optional)

What if I use multiple User Sources in Monosign and I want to specify my User Source for my Exchange?

For that, add an additional line to appSettings.


This setting refers to your Active Directory User Source or Domain Name on Monosign.

Like the following

User Source Name (Slug)

Or you can use the following Domain Name

Domain Name on User Source Settings

3- Sign In Test

Now try login in. Navigate to the Microsoft Exchange - OWA app. Click Monosign on the UI.


If you cannot sign in to OWA, the following reasons may cause this.

  1. The user needs to be assigned to the application

  2. The user needs to configure MFA properly

You can check the log files if you cannot see the error properly.

4- Troubleshooting

If you get any issue while trying to login OWA please take a look log files which are under the c:\monosign-logs

Issue 1 - Monosign API Access


[MONOFOR\john.smith] By-username result is 0 

By-username result is 0 means Exchange servers needs to be access monosign-api services. Please check your firewall to allow this communication.

Issue 2 - Invalid Key or Secret


[MONOFOR\john.smith] By-username result is OK {"InternalMessage":"Invalid Application Key","Code":12,"Success":false}
[] White listed: /owa/auth/errorFE.aspx?httpCode=500

{"InternalMessage":"Invalid Application Key","Code":12,"Success":false} means your application key or secret is invalid. Please check your application settings than verify configurations values in web.config on your Exchange.

Issue 3 - Permission Denied


[MONOFOR\john.smith] Mfa result is Forbidden {"Message":"Permission Denied","InternalMessage":"This user not assigned to this application.","Code":22,"Success":false}
[] White listed: /owa/auth/errorFE.aspx?httpCode=500

Mfa result is Forbidden {"Message":"Permission Denied","InternalMessage":"This user not assigned to this application.","Code":22,"Success":false} means your user has not assign to OWA application in the Monosign. Please assign this user than retry.

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