it could be that your running serato on 4 laptops, the limit is 3, you'll have to log out on one of them.

Only using one laptop. But thanks nonetheless.

so your using the license thats unlocked when you use the rane or did you buy a license?

make sure you're always connected to the internet when you start serato, so Serato can check your license, check your firewall make sure Serato is not block.

I've been to plenty of places where there's no internet and always able to start serato. Is there a way to verify if I'm using the license used to unlock Serato when I purchased my Rane One?

to unlock serato its basically plug and play, Plug your usb cable from controller to your laptop then run Serato and make sure your wifi is connected, Serato should check it and if it requires you to login then login with your serato account details and then you should be good to go.

also check this:

go into your serato account through your files browser, I use Brave browser its the best,
in your Serato account under "Manage Device" see how many computers connected to your account, it will tell you if you have 3 devices (3 is the limit) if you have then, just log out of one of them, then you can attach another computer to your account.

I just updated my serato about two weeks ago and all of a sudden today when I’m trying to set up for an event it says sub subscription expired and it wouldn’t let me use any of my expansion packs or nothing I had to go into serato and login and then it let me use them but at the bottom it still said subscription expired

Using a DDJ 1000 SRT which unlocks the subscription MacBook