Layers published from ArcGIS Pro 2.8 to Portal for ArcGIS cannot be added to maps using the GDA 1994 coordinate system

Description

Layers successfully published from ArcGIS Pro 2.8 to Portal for ArcGIS cannot be added to a map. The layers are displayed in My Contents in Portal for ArcGIS, but not on the map when they are added to it. The following severe error message is returned in the server log:

Error: 
<Layer Name>/FeatureServer: Unexpected character ('G' (code 71)): was expecting comma to separate Object entries at [Source: {"geoTransforms":[{"wkt":"GEOGTRAN["GDA_1994_To_WGS_1984_2",GEOGCS["GCS_GDA_1994",DATUM["D_GDA_1994",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHOD["Coordinate_Frame"],PARAMETER["X_Axis_Translation",0.06155],PARAMETER["Y_Axis_Translation",-0.01087],PARAMETER["Z_Axis_Translation",-0.04019],PARAMETER["X_Axis_Rotation",-0.0394924],PARAMETER["Y_Axis_Rotation",-0.0327221],PARAMETER["Z_Axis_Rotation",-0.0328979],PARAMETER["Scale_Difference",-0.009994]]","transformForward":false,"name":"GDA_1994_To_WGS_1984_2"}]}; line: 1, column: 38]

Cause

This issue occurs in maps using the GDA 1994 coordinate system. Australia changed its national coordinate system from GDA 1994 to GDA 2020, effective December, 2017. To reflect this change, Esri introduced a new transformation path, GDA 1994 To WGS 1984 2.

Beginning with ArcGIS Pro 2.8, the default map transformation system for projects using the GDA 1994 coordinate system is GDA 1994 To WGS 1984 2. This causes compatibility issues with ArcGIS Enterprise 10.9, as the new transformation is not included. The new transformation is available in ArcGIS Enterprise with the release of ArcGIS Enterprise 10.9.1. Refer to Esri Australia Technical Blog: New GDA2020 transformations for WebGIS for more information.

Solution or Workaround

In ArcGIS Pro, change the transformation path of the map containing the layers to GDA 1994 To WGS 1984 before publishing the layers to Portal for ArcGIS.

1. In ArcGIS Pro, in the Contents pane, right-click the map containing all the layers and click Properties.

2. In the Map Properties window, click Transformation.
3. For Transformation path, click GDA 1994 To WGS 1984 from the drop-down menu.
4. Click OK.