Hi @JustinMicheal-7973,
The new user's mailbox in the cloud is not created after waiting for 3 days.
Before we go on, would you mind clarfying a bit more about the issue you encounterd?
Are you trying to create a new mailbox in Exchange Online? If this is the case, it can be done by creating a new user in either the Microsoft 365 admin center or using the New-Mailbox command, then assign the user account a license for Exchange Online so that a mailbox is automatically created for the user. For more details, you may refer to Create user mailboxes in Exchange Online.
If you are in a hybrid environment and would like to create a new Office 365 Mailbox, the recommended way is to first add a new user in the on-premise Exchange Admin Center, sync the directory using AD Connect, and then assign a license to the user. For more details, hopefully you can find the article below helpful:
Creating an Office 365 Mailbox in a Hybrid Configuration
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
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