Model Export and Import - Error 40144

I'm trying to transport a model from one system to another and I get the following error when I try the Model export and import functionality in IBP 4.0

"errorCode":"40144","errorMsg":"Repository: delivery unit not found; deliveryUnit: 'SOP_MODEL_EXPORT_DU', vendor:sap.com'"

Steps:

1. Model Export -> Create Export

2. Once the Export is created, I clicked 'Download Deployment Unit' and that's when I get the above error.

Am I doing anything wrong? If so, what is the procedure to execute the model export and import between systems?