@Mohammed shakeeb Are you the administrator? Are you trying to import PST files to your own mailbox? See Import email, contacts, and calendar from an Outlook .pst file
Import PST file using Azcopy : https://learn.microsoft.com/en-us/microsoft-365/compliance/use-network-upload-to-import-pst-files?view=o365-worldwide
The only supported method for importing PST files to Microsoft 365 is to use the AzCopy tool, as described in this article. You can't use the Azure Storage Explorer to upload PST files directly to the Azure Storage area.
How To Import PST To Office 365 Using Azure AzCopy
If the issue still persist, please post your question in Microsoft 365 forum community These forum community members could provide their expert guidance on your scenario based on their experience. Thanks.
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