As this user: LibreELEC I have the same problem on my Odroid C2 device.
I'm using/testing LibreELEC (Krypton) v7.90.008 ALPHA on Odroid C2.
I can access to my QNAP NAS via SMB (Samba), I was able to create the Library and seen some videos, BUT after the reboot I cannot more access to all SMB share.... Error is: "Error 2: share not available" (on Debug log the error is: unix_err:'6e' error : 'Connection timed out').
I tried to reboot again but stil have this problem. If I try to access to others SMB source the problem is always "Error 2: share not available"...
I found a workaroud: change the WORGROUP to another name and then reset it to WORGROUP.
Hope in a fix.