"You do not have permission to access \\<
FLR path is not accessible.
"You do not have permission to access \\<<Unitrends IP>>.flr19. Contact your administrator to request access."
This error indicates that either the FLR path has been removed and is no longer available or the user attempting to access the data does not have the required permission.
If your Unitrends system is configured to enforce SMB2 but the system access the FLR share is not set to use SMB2, this error may occur. SMB2 enforcement can be disabled following How to disable SMB2 enforcement.
Alternatively, the WinSCP application can also be used to gain direct access to the files and folders on the Unitrends system.