Warning: Orders (Name = ******") is unlocated. Invalid input in the NA classes

Error Message

When attempting a solve operation on a network analysis layer using the Solve Vehicle Routing Problem tool in the Network Analyst extension in ArcMap, the following error occurs:

Error:   
"Warning: Orders (Name = ******") is unlocated.
Error: Invalid input in the NA classes."

Cause

This error occurs when there are no streets nearby the order, which is defined by users in the analysis layer.

Note:
Orders are parameters set in the Solve Vehicle Routing Problem tool, which routes where the Vehicle Routing Problem (VRP) geoprocessing service must visit. An order can represent a pickup, a delivery, or any other type of inspection or service.

Solution or Workaround

To solve the issue, use one of the following solutions:

• Turn off restrictions, if any. For more information, refer to the following document, ArcGIS Help: Understanding network attributes - Restrictions. When the restrictions are turned off, the tool does not try to look for restrictions or obstructions in the route, which may or may not exist.
• Check the 'Ignore invalid locations' check box in the Layer Properties dialog using one of the options. This allows the solve operation to ignore invalid network locations and only check from valid network locations in the analysis layer.

For more information, refer to the document, ArcGIS Help: Route analysis.