Constraint not met

In a Debug mode run, the solution misses this Add Constraint rule by the amount shown. Debug mode loosens your rules before anything else, so the rule is the first place to look, but the conflict may equally lie in the data it refers to.

What to do

Change the rule's number in the Add Constraint node to what the network can reach, change the data the rule refers to, such as a capacity or a demand, or remove the rule. Then turn Debug mode off and run again.

Where it comes from

Shown by Network Optimization. It is one of the messages about a node.