Didnt need the slaveOK part.

src/main/java/com/syncleus/maven/plugins/mongodb/StartMongoMojo.java

@@ -750,7 +750,6 @@ public class StartMongoMojo extends AbstractMongoMojo {
         getLog().info("Connected to MongoDB");
         final DB db = mongoClient.getDB("admin");
 
-        db.slaveOk();
         db.setWriteConcern(WriteConcern.UNACKNOWLEDGED);
         db.setReadPreference(ReadPreference.secondaryPreferred());
         BasicDBList membersList = new BasicDBList();