This is a little surprising, because that re-opening is always one of the major pre-requisites for the cease fire.
Merchants and manufacturers in Gaza say that the goods they have ordered are stuck in the Ashkelon port, and they cannot get them transported to Gaza. (They are also charged for storage at the port.)
The Gisha NGO says that only food, animal feed, humanitarian aid, medication, and fuel for international organizations are allowed into Gaza - not even fuel for the Gaza power plant. Nothing is being exported, either.
Perhaps there is some sort of security concern, but I cannot imagine what it is.
I know that the PA wants to be in the loop on allowing reconstruction materials into Gaza so there may be some political infighting between them and Hamas in allowing imports to resume - they have argued over tax collection from imports in the past.
Not re-opening the crossing in the way it was before could provide an excuse for the rockets to resume.