PS+ member and down for me today too. I reckon I'm just glad to know it isn't just me.
My playstation showed that I still had $10 in my wallet but I couldn't buy anything... Error code 80023102.
FIXED by logging into PSN Account Management from this link: https://store.playstation.com/login.gvm
Then "Edit Billing Information" to checked my Credit Card details. They had expired and actually I only had $1 in my account.
Fixed the credit card details and then topped up my Wallet "Add Funds: Credit Card" and all worked fine again.