The Routing Rule Tester screen explains why an order was routed to a particular printer.
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Note, the “U/R” column is the “Set Unvalid remote order” flag and the “U/M” column is the “Set Manual order unvalid” flag.
For each rule set up in the Routing Rule Designer (Setting Up Routing Rules), the expected value of a condition will be displayed (e.g. Sphere >= +2.00), and the actual value for the order will be shown underneath (e.g. +1.50/+1.75).
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