The path size used when publishing or saving a service definition file (.sd) exceeds the operating system limit. This path includes the path to the staging folder, the name of the server connection, and the path to the data's source data. This can also include paths within functional rasters.
The <value> parameter refers to the staging path, the input directory path on the server, or both, or the path to the data's source data.
If you are saving a service definition, the staging path is the location at which you specified to save the file.
Solutions
If your path exceeds the limit, you can shorten the staging folder path, service name, or the path to the data's source data to reduce the number of characters used for this path. When you share a web feature layer to ArcGIS Online, the name of the file geodatabase is limited to 66 characters.
More information
The Windows file system has limits to the number of characters that a path can contain. ArcGIS Pro issues a warning when the combination of the path to the staging folder and the server connection exceeds the size supported by the operating system. If the directory structure for service resources on the server exceeds operating system limits, the service cannot publish successfully.
For more information, see Analyze your GIS resource.