PowerShell – How to access Exchange Online Resource Mailbox Calendar

October 18, 2019

We are using the EVOKO Liso booking system, that is linked to Office 365 – Exchange Online

Where each meeting room has a tablet to book the rooms or equipment


Once booked on the Tablet it shows in Outlook, or the other way around.

If booked in Outlook it shows on the Tablet hanging on the wall beside the meeting room Smile


Fiarly easy to use and manage ..

But how to get access to the Exchange Online Resource Mailbox Resource Calendar

Or have a quick access to all bookings now and in the future Sad smile


First you need to check if the Resource Mailbox has the status PublishEnabled

Run this Powershell command and check the property : PublishedCalendarUrl

Get-MailboxCalendarFolder -Identity ResourceMailboxEmail@YourCompany.com:\calendar


If this is blank you need to set the Recourse Mailbox to PublishEnabled

Run this command to change it :

Set-MailboxCalendarFolder -Identity ResourceMailboxEmail@YourCompany.com:\calendar -PublishEnabled $true


Run the Get-MailboxCalendarFolder command again to check the result and copy the URL

You can also configure it using the OWA web interface


You can also set the permissions here, where you define the view permissions


Don’t forget the set the correct timezone / date and time format … for each resource calendar !



The URL exposed is not 100% correct in order to use it, you need to change it to HTTPS://….

At least now you can have a nice DAY / WEEK or MONTH overview  Smile


Keep in mind that it can take up to 24 Hrs to sync all of the intermediate changes in the calendar.

Exchange Online Calendar in SharePoint Online :

This is not supported see here  Sad smile

When you configure it all looks OK but there is an error message shown on top.

– Outlook Web Access URL : See above MailboxCalendarFolder : https://outlook.office365.com/owa/calendar/cef36771d9a042ec9d683890b1902915@……

– Exchange Web Service URL: https://outlook.office365.com/EWS/Exchange.asmx


Error :

The HTTP request is unauthorized with client authentication scheme ‘Ntlm’.

The authentication header received from the server was ‘Basic Realm=””‘.


But if you click the Overlay button it works by jumping to the Exchange Calendar Web Page.


Enjoy !!

MS Exchange – Grant permission to Distribution Groups in the GAL

February 3, 2015

Certain users in the organization where not able to edit (add / remove ) users from a Distribution group in the GAL.

This was the error they say in the Outlook.

“Changes to the public group membership cannot be saved …”


Nevertheless the user itself had Ownership ?


After Googling a bit, it seems that this is a dafault behavior of Exchange 2010 and higher.

So you need to change the Roles & Policies that are connected to the users, using the web ECP.

In order to allow the editing of the a Distribution Group from within Outlook.


Also the Membership Approval settings must be correct.


Next check the security settings via the ADUC on this Distribution Group Object. Make sure that this user has sufficient control.


Some more interesting readings are over here :



You can of course use PowerShell to manage the Distribution Groups

Using : Get-ManagementRole cmdlet

“get-managementrole MyDistributionGroupMembership | get-member”


Windows – AD User Password reset Tool

December 15, 2014

It has always been an issue to set up a self-service web facing Password Reset Tool.

Well if you have an Exchange server running let’s say 2010 SP1 or higher, you have all you need to make it work Smile

The only thing you need is to make an extra registry key entry in your CAS server. Which is in small organizations the same server as the Exchange backend server.

Solution :

  1. On the Client Access Server (CAS), click Start > Run and type regedit.exe and click OK.
  2. Navigate to HKLM\SYSTEM\CurrentControlSet\Services\MSExchange OWA
  3. Right click the MSExchange OWA key and click New > DWord (32-bit)
  4. The DWORD value name is ChangeExpiredPasswordEnabled and set the value to 1.
    Note: The values accepted are 1 (or any non-zero value) for “Enabled” or 0 or blank / not present for “Disabled”
  5. After you configure this DWORD value, you must reset IIS. The recommended method to reset IIS is to use IISReset /noforce from a command prompt.

Here is the result !


As of now your users can reset their passwords themselves Winking smile

PS : To check the Exchange version you can do this using the Outlook client.

Press CRTL + right click on the Outlook Icon in the system tray.

Select the Conntection status.


And read out the version column.


Or you can check the management console


Or you can use Powershell to do the job …

You can find the build numbers here :


Enjoy !

Exchange – hMailserver as Mail Relay Server

August 18, 2014

Recently I had a need for a Mail Relay server to function as a mail forwarding server to our hosted mail infrastructure.

The reason was that one of our devices was able to send out mail notifications. But only on the local domain servers.

So the solution was to put a Mail Relay server in the middle.

hMailServer is a fantastic free solution that can be a full replacement of you MS Exchange if you want !

1. Download the application


Once the application is downloaded and installed you can start the configuration.

2. configuration

First add your mail domain xxx@yourcompany.com to the server and the mail account to be used as sender.

The settings will appear in the General tab.


Next in the Settings -> Protocols -> SMTP -> Delivery e-mail tab, fill in the SMTP Relayer IP address and Port.


3. Set some Advanced Settings

In here you can set for the hMailServer the upper and lower IP addresses that are allowed to be sending e-mails to.


Make sure in the Require SMTP authentication nothing is ticket of the sender does not need to authenticate.

4. Run Diagnostics

As a last step Test your configuration using the Diagnostics Utility.


If everything turns GREEN then you are done.

As you can see the application supports as well MS SQL as well as PostgreSQL and MySQL. The hMailServer installation includes a minimal, built-in database server called Microsoft SQL Server Compact as a database server !

If you don’t specify a database it will use the MS SQL Compact edition. See here for some Tools

hMailServer Bonus

hMailServer comes with a COM library that can be used for integration with other software. Using the COM library, it’s possible to write scripts and full applications that utilize the features in hMailServer.

so you send mails using a script or download incoming mail attachments to a folder, or check the subject of an incoming mail and act upon it, or …

Here is an AutoIT script hMailServer Example.Smile


Exchange 2010 – Client Connection Issues

February 4, 2014

A while back I got a lot of complaints coming in from all over the place, regarding client connection issues. Where clients who logged in early in the morning where able to log in and others where not ? Sad smile

Interesting challenge. But since we are servicing a multi Timezone user base across the world. The heat was rising.

So first I thought it would be a client / internet connectivity related issue. But I was wrong.

After Googling a bit I found out that our parameters on the server where not set optimal when added more and more users and email domains to Exchange 2010.

So here is the solution :

Open the EMC and go to the server properties. Next to the LIMIT tab.


Change the Maximum Concurrent outbound Settings (and per Domain) to a more relevant number. Default it is 1000 and 20.

You will need to restart the Exchange Transport service when finished modifying these settings.

Also check the HUB Transport Global Settings – Max number of Recipients


More info you can find using Powershell to get hold of the ThrottlingPolicy Settings


if(!(Get-PSSnapin | 
    Where-Object { `

    $_.name -eq "Microsoft.Exchange.Management.PowerShell.E2010"})) {
      ADD-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010

Hope it can help solving your mysteries Winking smile