I've recreated the problem to catch the diagnostics.  2 sets attached.  rc1 where everything works fine on both coreelec and android.  rc3 where I cannot access shares from my coreelec install nor from my android phone.   The coreelec was told to use min SMB2 and max SMB3.  When rc3 threw errors, I dropped to min SMB1 and max SMB3 but there was no change to the behavior.   The kodi logs on the coreelec show the following under rc3, not sure if it's useful:   2019-10-