Switch-AzureRmWebAppSlot -SourceSlotName "staging" -DestinationSlotName "production" -Name "app1" -ResourceGroupName "group1" -verbose -SwapWithPreviewAction ApplySlotConfig

Switch-AzureRmWebAppSlot : Swap with Preview cannot be used when one of the slots has site authentication enabled.
At line:3 char:19
+ ... e-Command { Switch-AzureRmWebAppSlot -SourceSlotName "staging" -Desti ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : CloseError: (:) [Switch-AzureRmWebAppSlot], CloudException
+ FullyQualifiedErrorId : Microsoft.Azure.Commands.WebApps.Cmdlets.DeploymentSlots.SwitchAzureWebAppSlot