Thanks for finding the solution with SMB access. Instead I turned on NTLMv2 for Kodi on my Android box. Works fine again with Private security in Unraid.
Look here for a better explanation:
https://martinvanbeurden.nl/blog/xbmckodi-and-smb-access-denied/
I seem to have similar problem on an Android box. Upgraded to 6.3 and it works on my windows computers. But on a Android box where I use Kodi it will not access my SMB shares. If I instead use a filebrowser it will work accessing the files and thru that start Kodi.
Kodi works if I change the security in Unraid to Public from Private. So will use that until I got more time to look at it or if someone here finds a solution.