which from the date formats you specified do you expect to match against May 23, 2016? None of those data formats includes a comma and also not the format for the month in letters so I assume that this is the culprit. You need to add another date format.
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.