Issue Resolved.
Resolution:
- Technical critical information: It is very essential to understand what is the significance of the Root Folder of the Outlook IPM Tree folder structure/architecture. Root folder is called namely TopOfInformation It's so much critical that the command documentation pages should also have it's mentions.https://learn.microsoft.com/en-us/powershell/module/exchange/add-mailboxfolderpermission?view=exchange-ps
- ADD-MailboxFolderPermission -Identity xxx@domain.com:\ -AccessRights Reviewer -User abc@domain.com #this command is to provide top of information folder access
- Then run command specific to other folders like inbox and sent items.
ADD-MailboxFolderPermission -Identity "xxx@domain.com:\inbox" -AccessRights Reviewer -User abc@domain.com
ADD-MailboxFolderPermission -Identity "lou@domain.com:\SENT ITEMS" -AccessRights Reviewer -User abc@domain.com
- I found only 2 mentions that too hidden in the Graph documentations. https://learn.microsoft.com/en-us/outlook/troubleshoot/user-interface/incorrect-folder-names https://learn.microsoft.com/en-us/graph/api/resources/mailfolder?view=graph-rest-1.0