When performing configuration tasks for a utility network, the dataset does not have a valid Asset Type value that can be used.
Many configuration tasks rely on a classification system built into the feature class schema using the asset group and asset type attribute fields. The asset type field requires a valid attribute domain to be created and assigned to represent the minor classification of assets.
Review the network properties to ensure that the dataset has a valid Asset Type value.
Ensure that a valid attribute domain is created and assigned to the asset type field at the asset group (or subtype) level. See Configure a utility network and View and edit subtypes in the Subtypes view for information about assigning attribute domains to fields for specific subtypes.