Its because of the recent policy of the Naira redesigning and cashless policy. It's a policy not well thought in defense of going fully cashless.

The banks are boarding the new notes which most likely are been move to the politicians considering the coming election.

It's much worse because even the electronic channels are not to be relied upon (bank apps are shitty) and old notes are been phased out of circulation.

I personally have been out of cash for weeks now.