Hi @Joyce Mulbah ,
the Global Administrator
is related to Microsoft Entra Id (Microsoft Entra roles).
This allows you to manage Entra Id only.
For managing objects in Azure Subscriptions you need to be Owner
or Contributor
on subscription level in Azure as well: Azure roles
Please verify your user is member in a related Azure RBAC role to create a VM in your subscription.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten