No ROOT or Private folders exist

Hello Experts,

I have a CF Document Management Service (Application Option) connected to my ABAP CMIS repository. I followed this link-(Connect SAP Document Management, Application Option to DMS) to do so.

However when I opened the web application, I got this error.

It is an error come from ABAP system, I already have my ABAP system configuration done following steps mentioned in this link-How to connect SAP Mobile Documents (HCP edition) to an ABAP System – Part I. Even the Content Server I use the same one mentioned in this post where I'm not sure if it is correct.

By having done some research, I found this Funtion Module - "DMS_MDOC_SHOWROOTFOLDERS" that can be run to check ROOT folders. But in my ABAP system, it returns empty value for PUBLICFOLDER.

How can I have a ROOT folder? Anyone can help here? Or is it the root cause that I got the error?

Thanks a lot!

Chunyang