Error: Unable to retrieve the information for existing item.
Depending on the cause, use one for the following workflows to resolve the issue.
Migrate the ArcMap service runtime to the ArcGIS Pro service runtime
If a service is created in ArcMap and uses the ArcMap service runtime, the service cannot be overwritten as the ArcMap service runtime has been deprecated. Refer to ArcGIS Server: Migrate a service to the ArcGIS Pro service runtime for instructions on updating a service to the ArcGIS Pro service runtime.
Use the correct map ArcGIS Server URL when connecting to ArcGIS Pro
When adding a server connection in ArcGIS Pro, ensure that the server URL is formatted as follows:
Republish the map service
Recreate the map service in ArcGIS Pro and publish it. Refer to ArcGIS Pro: Publish a map service for instructions.
Ensure that the map service is running in ArcGIS Server Manager
Navigate and sign in to ArcGIS Server Manager as an administrator, and ensure that the map service is running. If the map service is not running, refer to ArcGIS Server: Start a service in Manager for instructions on starting a service.
Remove the join or make the join in the layer permanent in ArcGIS Pro
Export the layer with the join to a new feature class and use this new feature class in the map to be published.
Alternatively, remove the joins from the layer before publishing it.