No, not Sessions but possibly some of the Obummer holdovers or others who work at the DOJ and FBI are withholding and slowing things down.
Remember when Gowdy was so frustrated trying to get info when he was investigating and Obummer was President? Dosesn’t look like a change of President has made much difference, maybe they need an investigation to determine why it is so difficult getting the necessary docs and stuff they need, ridiculous.