Hi @Jan Fimbinger ,
maybe this PowerShell script helps to identify the related Azure Tenant (Azure AD) of an Azure Subscription. The Az Powershell module is required.
Connect-AzAccount
$tenantID = (Get-AzSubscription -SubscriptionName "<xyz Subscriptionname> ").TenantId
Get-AzTenant -TenantId $tenantID
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten