Here is an error that I’ve seen on couple installations:

SMS Active Directory System Discovery Agent failed to bind to container LDAP://DC=domain,DC=xxx. Error: The server does not support the requested critical extension.
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Possible cause: The AD container specified earlier might be invalid now. The Domain Controller is inaccessible.
Solution: Please verify that the AD container paths specified are valid. Confirm accessibility of the site server to the Domain Controller to be queried. (more…)