[Samba] unavailableCriticalExtension (12)

[Kristofer Pettijohn]

I am attempting to set up AWS Directory Services to connect with our Samba 4 AD servers, but it is not working. When capturing with Wireshark, I am seeing that Samba 4 is returning "unavailableCriticalExtension (12)" 

Below is a screenshot of the LDAP query. Sorry, I couldn't figure out how to get Wireshark to copy and paste it all to plain-text. 

Does anyone have any hints as to what might the issue might be?