Comment 2 for bug 1634119

Thank you for taking the time to report this bug and helping to make Ubuntu better. Also a huge thank you for already collecting the additional data.

From the logs:
WARNING: Ignoring invalid value 'share' for parameter 'security'
error opening config file '/etc/samba/smb.conf'

As you noted the share parameter appears to be keeping things from working. A quick search shows that share=security is deprecated. A quick search of the community forums found this page: https://ubuntuforums.org/showthread.php?t=1962617 which may help you.

Since this appears to be a local configuration problem and not a bug in Ubuntu, I'm marking this bug as Incomplete. We'd be grateful if you would then provide a more complete description of the problem, explain why you believe this is a bug in Ubuntu rather than a problem specific to your system, and then change the bug status back to New.

If indeed this is a local configuration problem, you can find pointers to get help for this sort of problem here: http://www.ubuntu.com/support/community