Putaway Rule where only criteria is Putaway type is "blank"

Summary:

Need to create a putaway rule for items that have no putaway type. The item putaway type is blank so it needs to be directed to a certain area of the facility. I have tried creating putaway rule for this, but I am not having luck. I have Putaway type, replenishment zones and putaway priority set up like all my other putaway rules but still get same error. "Could not calculate putaway type. Check configurations!"

What can I use for "blank"? I have tried multiple different ways. *Null *, %blank%, ""

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