Recieving (403) Forbidden when Accessing Dataset via API

I am getting an error when accessing dataset via API.

This was previously working but I suspect someone made some changes to that dataset.  However, I know that both the service principle and the impersonating user have admin on that dataset.  I have also tried to create another service principle, following the guidance in

Embed Power BI content in an embedded analytics application with service principal and an application secret - Power BI | Microsoft Learn

And I get the same result.

I have confirmed the setting 'Allow service principals to use Power BI APIs' remains enabled.

I am able to access the dataset OK with the impersonating user.

I have tried granting the service principal API access to datasets in Azure AD (even though I dont think that is required)

$clientId = "0bXXXXc6"
$clientSecret = "GSXXXXaE"

# Function to get the access token
function Get-AccessToken {
    param (
        $tenantId,
        $clientId,
        $clientSecret
    )

    $tokenEndpoint = "https://login.microsoftonline.com/$tenantId/oauth2/token"
    $body = @{
        "grant_type"    = "client_credentials"
        "client_id"     = $clientId
        "client_secret" = $clientSecret
        "resource"      = "https://analysis.windows.net/powerbi/api"
    }

    $response = Invoke-RestMethod -Uri $tokenEndpoint -Method Post -Body $body -ContentType "application/x-www-form-urlencoded"
    return $response.access_token
}

# Get access token
$accessToken = Get-AccessToken -tenantId $tenantId -clientId $clientId -clientSecret $clientSecret

$headers = @{
    "Authorization" = "Bearer $accessToken"
}


$url = "https://api.powerbi.com/v1.0/myorg/datasets/403358d8-a148-4d52-a33f-4d39630ddb78/executeQueries"
$body = @"
{
    "queries": [
        {
           "query": "EVALUATE SUMMARIZECOLUMNS('Geography'[Store Number], 'Geography'[Store Opening Hours 1.Monday], 'Geography'[Store Opening Hours 2.Tuesday], 'Geography'[Store Opening Hours 3.Wednesday], 'Geography'[Store Opening Hours 4.Thursday], 'Geography'[Store Opening Hours 5.Friday], 'Geography'[Store Opening Hours 6.Saturday], 'Geography'[Store Opening Hours 7.Sunday], 'Geography'[Store Opening Hours 8.Special])"
        }
    ],
    "serializerSettings": {
        "includeNulls": true
    },
    "impersonatedUserName": "[email protected]"
}
"@

$result = Invoke-WebRequest -Uri $url -Method Post -Body $body -Headers $headers -ContentType "application/json" -UseBasicParsing -Verbose -Debug

Invoke-WebRequest : The remote server returned an error: (403) Forbidden.
At line:59 char:11
+ $result = Invoke-WebRequest -Uri $url -Method Post -Body $body -Heade ...
+           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand