Fixed – Access Denied (CryptographicException) on calling SharePoint Online APIs using Azure AD App-Only


While trying to call SharePoint Online APIs using Azure AD App-Only using Certificate Auth we were getting the Access Denied exception.

We were creating the ClientContext using the AuthenticationManager class of PnP the Framework and were using Certificate Auth as shown below.

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This was because the console app was trying to create a key in the machinekeys folder and the user did not have Write access to it.

C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys

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We provided the Write access, which fixed the issue.

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We can see the keys added to that folder and SharePoint Online APIs called successfully

Hope it helps..

Sample code to check if a Folder exists else create it (SharePoint Online / PnP Framework / C#)


Sharing the sample code that we can use for checking if a particular folder exists and if not then create it in SharePoint Online. It uses PnP Framework and Azure Ad App only permissions.

Here we have used the PnP Framework Library in our console application.

We will be checking for and creating the folder at the below location.

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On a successful run, we can see the folder named “MyFolder” created the document library.

Below is the sample code

static void Main(string[] args)
        {
            var siteUrl = "https://w72tk.sharepoint.com/sites/MyTeamSite";          
            var applicationId = "d7eaeeb7-ef0a-474d-9b94-567013576c14";
            var password = "xyz";
            var domain = "w72tk.onmicrosoft.com";
            var certPath = @"C:\SharePointApp\MyTestCertificate.pfx";

            var authManager = new AuthenticationManager(applicationId, certPath, password, domain);
            var foldertoCheck = "MyFolder";
            using (var clientContext = authManager.GetContext(siteUrl))
            {
                var currentWeb = clientContext.Web;
                var folderExists = currentWeb.DoesFolderExists(foldertoCheck);
                if (!folderExists)
                {
                    var list = clientContext.Web.Lists.GetByTitle("Documents");
                    list.RootFolder.Folders.Add(foldertoCheck);
                    clientContext.ExecuteQuery();
                }
            }
        }

Refer for more details – https://nishantrana.me/2024/07/30/calling-sharepoint-online-api-using-azure-ad-app-only-permissions-using-certificate-auth/

Hope it helps..

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Calling SharePoint Online API using Azure AD App-Only permissions using Certificate Auth


Below are the steps we need to follow to call SharePoint Online API through a Console App (C#).

The first step is to register an Azure AD app.

Provide appropriate SharePoint API Permissions

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As the console app would run in the background we opted for Application Permissions.

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For testing, we opted for Sites.FullControl.All permission.

Also, Grant the admin consent

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Next, we need to generate and upload the certificate

Run the below PowerShell script to generate the self-signed certificate

.\Create-SelfSignedCertificate.ps1 -CommonName “MySampleCertificate” -StartDate 2024-01-01 -EndDate 2026-10-01

#Requires -RunAsAdministrator
<#
.SYNOPSIS
Creates a Self Signed Certificate for use in server to server authentication
.DESCRIPTION
.EXAMPLE
.\Create-SelfSignedCertificate.ps1 -CommonName "MyCert" -StartDate 2015-11-21 -EndDate 2017-11-21
This will create a new self signed certificate with the common name "CN=MyCert". During creation you will be asked to provide a password to protect the private key.
.EXAMPLE
.\Create-SelfSignedCertificate.ps1 -CommonName "MyCert" -StartDate 2015-11-21 -EndDate 2017-11-21 -Password (ConvertTo-SecureString -String "MyPassword" -AsPlainText -Force)
This will create a new self signed certificate with the common name "CN=MyCert". The password as specified in the Password parameter will be used to protect the private key
.EXAMPLE
.\Create-SelfSignedCertificate.ps1 -CommonName "MyCert" -StartDate 2015-11-21 -EndDate 2017-11-21 -Force
This will create a new self signed certificate with the common name "CN=MyCert". During creation you will be asked to provide a password to protect the private key. If there is already a certificate with the common name you specified, it will be removed first.
#>
Param(

[Parameter(Mandatory=$true)]
   [string]$CommonName,

[Parameter(Mandatory=$true)]
   [DateTime]$StartDate,

[Parameter(Mandatory=$true)]
   [DateTime]$EndDate,

[Parameter(Mandatory=$false, HelpMessage="Will overwrite existing certificates")]
   [Switch]$Force,

[Parameter(Mandatory=$false)]
   [SecureString]$Password
)

# DO NOT MODIFY BELOW

function CreateSelfSignedCertificate(){

#Remove and existing certificates with the same common name from personal and root stores
    #Need to be very wary of this as could break something
    if($CommonName.ToLower().StartsWith("cn="))
    {
        # Remove CN from common name
        $CommonName = $CommonName.Substring(3)
    }
    $certs = Get-ChildItem -Path Cert:\LocalMachine\my | Where-Object{$_.Subject -eq "CN=$CommonName"}
    if($certs -ne $null -and $certs.Length -gt 0)
    {
        if($Force)
        {

foreach($c in $certs)
            {
                remove-item $c.PSPath
            }
        } else {
            Write-Host -ForegroundColor Red "One or more certificates with the same common name (CN=$CommonName) are already located in the local certificate store. Use -Force to remove them";
            return $false
        }
    }

$name = new-object -com "X509Enrollment.CX500DistinguishedName.1"
    $name.Encode("CN=$CommonName", 0)

$key = new-object -com "X509Enrollment.CX509PrivateKey.1"
    $key.ProviderName = "Microsoft RSA SChannel Cryptographic Provider"
    $key.KeySpec = 1
    $key.Length = 2048
    $key.SecurityDescriptor = "D:PAI(A;;0xd01f01ff;;;SY)(A;;0xd01f01ff;;;BA)(A;;0x80120089;;;NS)"
    $key.MachineContext = 1
    $key.ExportPolicy = 1 # This is required to allow the private key to be exported
    $key.Create()

$serverauthoid = new-object -com "X509Enrollment.CObjectId.1"
    $serverauthoid.InitializeFromValue("1.3.6.1.5.5.7.3.1") # Server Authentication
    $ekuoids = new-object -com "X509Enrollment.CObjectIds.1"
    $ekuoids.add($serverauthoid)
    $ekuext = new-object -com "X509Enrollment.CX509ExtensionEnhancedKeyUsage.1"
    $ekuext.InitializeEncode($ekuoids)

$cert = new-object -com "X509Enrollment.CX509CertificateRequestCertificate.1"
    $cert.InitializeFromPrivateKey(2, $key, "")
    $cert.Subject = $name
    $cert.Issuer = $cert.Subject
    $cert.NotBefore = $StartDate
    $cert.NotAfter = $EndDate
    $cert.X509Extensions.Add($ekuext)
    $cert.Encode()

$enrollment = new-object -com "X509Enrollment.CX509Enrollment.1"
    $enrollment.InitializeFromRequest($cert)
    $certdata = $enrollment.CreateRequest(0)
    $enrollment.InstallResponse(2, $certdata, 0, "")
    return $true
}

function ExportPFXFile()
{
    if($CommonName.ToLower().StartsWith("cn="))
    {
        # Remove CN from common name
        $CommonName = $CommonName.Substring(3)
    }
    if($Password -eq $null)
    {
        $Password = Read-Host -Prompt "Enter Password to protect private key" -AsSecureString
    }
    $cert = Get-ChildItem -Path Cert:\LocalMachine\my | where-object{$_.Subject -eq "CN=$CommonName"}

Export-PfxCertificate -Cert $cert -Password $Password -FilePath "$($CommonName).pfx"
    Export-Certificate -Cert $cert -Type CERT -FilePath "$CommonName.cer"
}

function RemoveCertsFromStore()
{
    # Once the certificates have been been exported we can safely remove them from the store
    if($CommonName.ToLower().StartsWith("cn="))
    {
        # Remove CN from common name
        $CommonName = $CommonName.Substring(3)
    }
    $certs = Get-ChildItem -Path Cert:\LocalMachine\my | Where-Object{$_.Subject -eq "CN=$CommonName"}
    foreach($c in $certs)
    {
        remove-item $c.PSPath
    }
}

if(CreateSelfSignedCertificate)
{
    ExportPFXFile
    RemoveCertsFromStore
}

Specify the password and note it down as it will be used for connection.

Upload the certificate to the Azure AD App registered.

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For the console app, we installed the PnP.Framework Nuget Package

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The sample code –

           try
            {
                var authManager = new AuthenticationManager(applicationId, certPath, password, domain);
                using (ClientContext clientContext = authManager.GetContext(siteUrl))
                {
                    var folder = clientContext.Web.GetFolderByServerRelativeUrl(folderRelativeUrl);
                    clientContext.Load(folder);
                    clientContext.Load(folder.Files);
                    clientContext.ExecuteQuery();

                    foreach (var file in folder.Files)
                    {
                        if (countFilesToImport < maxFilesPerCycle)
                        {
                            _filesToImport.Add(file);
                        }

                        countFilesToImport++;
                    }
                }
            }
            catch (Exception ex)
            {
                System.Console.WriteLine("Error: " + ex.Message);
                if (ex.InnerException != null)
                {
                    System.Console.WriteLine("Inner Exception: " + ex.InnerException.Message);
                }
            }
        }

We can see our app is successfully connected.

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The other option is to use the SharePoint app-only, which is not recommended by Microsoft.

We can see the following message for it.

Starting April 2, 2026, Azure Access Control service (ACS) usage will be retired for SharePoint in Microsoft 365 and users will no longer be able to create or use Azure ACS principals to access SharePoint. Learn more about the Access Control retirement

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Get all the details here

Hope it helps..

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Set an app (Model-driven or Canvas App) as a startup app – Power Apps Mobile


Microsoft has introduced a new feature, through which we can now specify a particular app as a start-up app, that will open up when we launch the Power Apps mobile, instead of waiting for the home page / or selecting it from favorites.

Below we can select the option Open at Startup to specify the Customer Service Hub app as the startup app as an example.

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Or we can swipe left to mark an app as “Startup App

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We can see an icon next to the app.

Now launching the Power Apps mobile app will directly open the Customer Service Hub app.

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Using the Remove from startup option we can remove it as the startup app

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We can only have one app set as a startup app, if we try setting up another app as a startup we get the notification that it will replace the existing app.

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Get all the details here

Hope it helps..

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Mobile Offline Profile – Select columns to be downloaded (Dynamics 365 / Model-driven apps)


With this new feature (preview) now we can specify the columns to be downloaded on mobile devices for offline use.

Select edit for the Model-driven app.

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Select Settings and select an existing offline profile or create a new profile.

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Select a new table or an existing table for the profile, we can see the Manage Columns option for it.

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We can see key columns already selected as part of Required Columns.

We can select columns from the other columns section for our offline profile. The fewer the columns the faster the app will download the data for offline usage.

One point to note is that we get this option only from the Maker Portal not from the Power Platform Admin Center.

Hope it helps..

Perform Age calculation using Formula Columns in Dataverse / Dynamics 365


Below we have created a new field of Data Type Formula and Formula Data Type as Whole Number

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Specify the following formula.

RoundDown(DateDiff(birthdate, UTCNow(), TimeUnit.Days) / 365.25, 0)

  • DateDiff calculates the difference in days between birthdate and current UTC Date.
  • Dividing by 365.25 takes care of converting the days to years, considering the leap year into account.
  • Roundown takes care of rounding the result to a nearest integer.

Below we see the field in action.

UTC current date is 10th Wednesday July 2024 for the below example.

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Also checkout the helpful video –

and the forum – https://powerusers.microsoft.com/t5/Microsoft-Dataverse/Calculating-age-in-CDS-entity/td-p/495528

Hope it helps..

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