My cloud Sharepoint - progress bar not moving

I have a 4tb Mycloud attached via a BT Homehub and have had some difficulties with my Timemachine Backups. Through discussions with Apple and WD, I have been advised to make a backup so we can investigate and move forward.
I have purchased a WD My Passport (non SSD) and connected to the My Cloud USB port.
After a few failed attempts - I have managed to create a sharepoint and begin a backup. There is a small blue block on the progress bar but this does not seem to get any longer even after a few hours - I have tried a few times and even started from scratch (formatting the new drive to save confusion!) Is this normal… ?

You should refer the link mentioned below to know the NAS to USB feature given in My Cloud Device.