There are so may post on different forums talked about this but none seem to talk on the point.
Follow these steps and you should be able to access your Synology NAS volume.
Step 1: Set NFS Permissions
Set NFS permissions in your NAS: Control Panel >> Shared Folder >> Choose the Folder you would like to access >> Click on Edit >> Click on NFS Permissions >> Creat NFS Permissions
You may like to review the link below which explains greatly, however, the mounting part doesn’t work as explained in the article below.
Step 2: Mount
Use the command below to mount Synology NAS volume to your Linux distribution you use.
sudo mount -t cifs -o user=your-user-name,domain=.,password=your-password //NAS-IP/share-folder /mount-path
sudo mount -t cifs -o user=music,domain=.,password=MyPass321$ //192.168.1.1/music /home/pi/music/
Note: You do not need to use volume1 as shown in your Synology NAS.
A very good post about the mount command you can find here if you get an error message like: