Hi Ramiro Larenas,
Could you share more details about the issue, so that we can assist you correctly.
Are you in the part of same subscription which you are trying to delete?
Do you have contributor or owner access to the VMSS’s subscription and tenant?
Can you specify which Azure service or resource the VMSS is associated with like Azure Kubernetes Service (AKS), Azure Lab Services, Azure DevOps, Application Gateway?
Can you confirm which Azure Active Directory (AAD) tenant your user account is currently authenticated against?