DOCSP-26370: FAQ entry for MongoSecurityException (mongodb#427)

* DOCSP-26370: FAQ entry for MongoSecurityException

(cherry picked from commit 1b0a35e)

Author: Chris Cho

source/faq.txt

@@ -176,10 +176,32 @@ your classpath, check the following items in your environment:
    :ref:`API documentation <java-api-landing>`.
 
 
+How do I prevent the "com.mongodb.MongoSecurityException" error?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Your application might throw this exception if you specify invalid or
+incorrectly formatted credentials when connecting to a MongoDB deployment.
+
+If you receive this error when you attempt to connect to a MongoDB deployment,
+check the following items in your code:
+
+- The connection URI corresponds to the correct MongoDB deployment.
+  To learn more about setting your connection URI, see :ref:`connection-uri`.
+
+- The credentials for the authentication mechanism that you specified are
+  correct. To learn how to specify your credentials, see the
+  :ref:`authentication-mechanisms` and :ref:`enterprise-authentication-mechanisms`
+  guides.
+
+- The name of the authentication database that you specified is correct. To
+  learn how to set up the users and roles for your MongoDB deployment, see
+  `Manage Users and Roles <https://www.mongodb.com/docs/manual/tutorial/manage-users-and-roles/>`__
+  in the Server documentation.
+
 How do I prevent the "IllegalArgumentException: Invalid BSON field name" error?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Your application may throw this exception if you pass an incorrectly formatted
+Your application might throw this exception if you pass an incorrectly formatted
 document to an operation and you are using a driver version v4.7 or earlier.
 
 .. note::