2022-10-11 14:31:16 INFO: {Line:246} Setting MIP Label for \\TEST_FILESERVER\home\SecurityTest\TestFile.docx files
2022-10-11 14:31:33 ERROR: {Line:283} Caught an exception.
In function[setMIPLabels] at Line[250].
Exception Type[Microsoft.InformationProtection.Exceptions.JustificationRequiredException].
Exception Message[Justification is required].
Complete Exception:
Microsoft.InformationProtection.Exceptions.JustificationRequiredException: Justification is required
at Microsoft.InformationProtection.File.Implementation.FileHandlerImpl.SetLabel(Label label, LabelingOptions labelingOptions, ProtectionSettings protectionSettings)
at Microsoft.InformationProtection.Powershell.AIP.Commandlets.SetAIPFileLabelCmdLet.
2022-10-11 14:31:33 INFO: {Line:362} Exiting with code[200].
In the Microsoft Compliance Portal, User must provide a justification to remove a label or lower its classification is selected but no Justification Message is configured

In order to remove/replace the existing MIP label with a lower-order MIP label, one must configure a Justification Message if the policy User must provide a justification to remove a label or lower its classification is selected
To add a Justification Message:
In the Data Insight console, navigate to Settings -> Remediation -> Data Management -> Set MIP Label -> Justification Message