NFS Client on DietPi and Backup

I used WebMin on a Ubuntu server to create an NFS export. The export is on an ext4 formatted drive.
I created an NFS client on DietPi and directed it toward the server IP via the Dietpi-Config routine.
I created a file on the DietPi and saved it on the NFS share - verified it showed up … so all is OK.

When I direct the DietPi-Backup process to the “list”, the NFS share shows up.
When I try to select the NFS share the error below shows up …

/mnt/nfs_client/xxxxx/rlamans/yyyyy/dietpi-backup Has a
filesystem of: , and is not supported.

The filesystem must be EXT2/3/4 for symlink compatibility.

Any help would be appreciated. I don’t know what log to include either.
Robert Amans