Error The mailbox is either inactive, soft-deleted, or is hosted on-premise. even I can access Mailbox

[Ammadshafi]

But I am getting the Error The mailbox is either inactive, soft-deleted, or is hosted on-premise. even I can access mailbox of my email i am just trying to access the mail of my app user using @microsoft/microsoft-graph-client

[moghimi]

I believe you need to buy a valid M365 license, see this link: https://learn.microsoft.com/en-us/answers/questions/761931/microsoft-graph-api-throws-the-mailbox-is-either-i