@smieschek yup that's what I was talking about, the rpi3 is the same rpi3 that I had registered under my other license under a different account name, which was nishirams@gmail.com, what happened was I was asked to update my pi3 during my last install and after updating, it refused to boot up. So I reinstalled a fresh copy of the latest emteria for pi3 then the issue started that I couldn't register it after installation. I then tried with a new account I created which is this account arianrivvrr@gmail.com and the same thing happens.
Yes I also have a rpi4b so I tried with it and it worked with this account.
I don't know why the rpi3 just refuses to register with both the accounts keeping in mind that this same rpi3 was previously registered with the same ID used before the fresh install
Any idea why it does that?