DDJ-400 not connecting to recordbox on my laptop

Hi everyone, This is my first post I have a laptop with windows 10 running recordbox. I bought a DDJ-400 about 6 months ago, it been working fine all that time. I had to pack away my ddj over dec and got it out last weekend. Booted up my laptop and updated to the latest recordbox then plugged my ddj in and it won’t connect. The ddj lights up so is getting power but recordbox does not connect to it and I can’t control anything with the ddj. Tried changing various settings after looking online and also reinstalled the latest firmware but nothing seems to work. Absolutely gutted at the minute, please can anyone help!?