New User - Backups Fail

I am trying out Backup & Recovery 17 CE for the first time

MS Surface Pro 3
Windows 10 Pro
Samsung SSD with 138 GB used

I am backing up to a target drive on my Synology NAS
The Paragon backup is configured as follows

• Full backup/entire PC
• No retention
• Paragon Image
• Normal compression
• Do Not Split/3.91 GB (tried both)

I am mapped to my NAS backup drive so I first tried backing up to it as a Local Drive
This failed with the error: 0x11009

I then defined the backup target as a network location using the UNC
This failed with the error "the operation is not implemented" 0x100a4

With both attempts-

• The remaining time to complete the backup time initially displayed just a few minutes but then gradually increased and kept growing.
• the brv.log shows
  !!!Error: Copy basic disk 0 to disk 2 (1 of 1) ... Failed (Result = 0x100a4, "F:\BuildAgent\work\b920704471b5a205\hdmengine\hdmsdk \src\stub1\vdarc\vdarccore.cpp, line 5899")

However, I have no drive F:

Any help much appreciated!