An Azure service that is used to manage and protect cryptographic keys and other secrets used by cloud apps and services.
Hi, you can’t delete those old tenants because you’re not an admin in them anymore. If they came from previous jobs, your account is still listed in those directories, but you don’t have the permissions needed to remove the tenant, so Azure shows “You don’t have access”. Only someone who is a Global Admin in those organisations can either delete the tenant or remove your account from it.
This doesn’t affect your Key Vault; you just need to make sure you’re signed into the correct tenant in the Azure portal (top-right → Switch directory). Once you’re in the right directory, your Key Vault should be accessible. The old tenants will stay there until their admins remove you.