Your layer is using a feature class with a representation rule that has a custom geometric effect or custom marker placement. Custom representation rule geometric effects or marker placements are not supported. The rule with the problem will be indicated by the <value> parameter.
- Change your representation rule to geometric effects and marker placement provided by ArcGIS Pro. The provided solution will open the representation symbology properties of the layer so the properties can be edited.
- If you do not need this layer you can remove it from the map.
Representations provide advanced capabilities for symbolizing your data. ArcGIS Pro includes a variety of geometric effects and marker placements that meet most common cartographic specifications.