Hi Matt,
When you are given access to another tenant's resources you must use the switch directory feature:
When activating your subscription, your identity is created based on the email you use. That identity is either associated with your organization’s Active Directory tenant or a new directory tenant is created for that identity. You can see the identity you’re using in the upper right-hand side of your Azure portal.
From here, you can either switch identities or switch directories. You may need to change your identity to access certain directories.
If the identity you’re logged in as is associated with multiple directories, switch by selecting “Switch directory.” You'll see the directories your current identity is associated with.
If this is helpful please accept answer.