@Danp yes, I'm getting this error on the settings > remotes page.

As you can imagine, I'm confused why NFS works on the main SR page, but not the settings > remotes page

EDIT: never mind, discovered that I have to put the full share path, not just the share name.

Example:

\\10.69.50.31:Port:/mnt/user/UnraidBackup/XCPNGBackups