Years ago Clio built an integration with NetDocuments. The main purpose is to push clients and matters created in Clio to NetDocuments.
Recently I turned it on at a firm and was running into this error message.
Failed to create the Link. You may not have sufficient permissions.
Finally with the help of NetDocuments Support, I was able to fix this.
In NetDocuments, Go to Admin –> Users and Groups.
Open up the Internal Users Group
Check the Box next to Members are allowed to upload lookup tables. This will allow any users to create new client and matter profile attributes.