Congratulations on pursuing the AZ-104 Azure Administrator Certification! I wish you the best of luck on your learning journey.
I want to reassure you that if you are following the Azure learning path for any Microsoft certification, all the lab exercises conducted in the sandbox environment are entirely free of charge. So, there's no need to worry about any costs on your end.
Regarding the error message you mentioned while trying to open the sandbox environment for Azure PowerShell, it likely seems to be some authentication issues. If you could provide me with the exact error message, I'd be happy to assist you further and provide a more detailed explanation.
If this response resolves your query, please consider clicking "accept answer."