On adding series from disk

Version
2.0.0.5344
Mono Version
4.6.2
AppData directory
/var/snap/sonarr/common
Startup directory
/snap/sonarr/225/NzbDrone

I tried adding my NAS drive /mnt/synology/media/tv, which contains my tv folders. When I try to access it, I get “Folder is not writable by user root”. I installed this from the snap store on Ubuntu 18.04, and have not seen this issue before. What am I missing?