Hi Lendrix68,
There is my setup, it might help.
Don't for get to check you Synology NFS sharing folder with permission and your Pi's ip.
The mine is in DSM 5.1
https://www.synology.com/en-global/knowledgebase/tutorials/566- Attachments

- NAS-path.png (146.41 KiB) Viewed 9385 times