Azure Function Key Management API - Authentication error

Question

I have two Azure function apps, both in the same Azure subscription. I can retrieve keys for one but not for the other. As far as I can see there is no difference between the two function apps.

I'm using this Powershell code:

function GetHostKey
{
    param($webAppName, $resourceGroupName)

    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

    Write-Host "Getting master key from $webAppName"

    $xml = [xml](Get-AzureRmWebAppPublishingProfile -Name $webAppName -ResourceGroupName $resourceGroupName -Format WebDeploy -OutputFile null)
    $msdeployUsername = $xml.SelectNodes("//publishProfile[@publishMethod=`"MSDeploy`"]/@userName").value
    $msdeployPassword = $xml.SelectNodes("//publishProfile[@publishMethod=`"MSDeploy`"]/@userPWD").value

    $apiBaseUrl = "https://$webAppName.scm.azurewebsites.net/api"
    $siteBaseUrl = "https://$webAppName.azurewebsites.net"

    $base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $msdeployUsername,$msdeployPassword)))
    $jwt = Invoke-RestMethod -Uri "$apiBaseUrl/functions/admin/token" -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)} -Method GET

    $uri = "$siteBaseUrl/admin/host/systemkeys/_master"
    $response = Invoke-RestMethod -Uri $uri -Headers @{Authorization=("Bearer {0}" -f $jwt)} -Method GET
    return $response.value
}

The call to $siteBaseUrl/admin/host/systemkeys/_master returns the expected json for one function app, but the other one returns a login screen.

Answer 1

Compare both functions settings, versions. Try to get the keys manually from the portal to isolate the source of the problem. I had the same problem till i deleted and recreated the functions.