CmdID

CmdID / PowerShell / Cmdlets / Remove

Remove-BlockedSenderAddress

Use the Remove-BlockedSenderAddress cmdlet to unblock users in your Microsoft 365 organization that were affected by the protection system. Exchange PowerShell reference

From the Exchange PowerShell reference 2 parameters Its page in the reference

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Parameters

2 in the Exchange PowerShell reference
-SenderAddressThe SenderAddress parameter specifies the email address of the user that you want to unblock.
-ReasonThe Reason parameter specifies the reason the user was blocked (the Reason property value).