Delphi Community Edition registration limit reached for specific serial number

This appears to have happened before with other users, but what I don't understand is why?

I have several Delphi CE's on a NUC, a laptop and two desktops in my house, just to be able to write programs at the spot I will use them. Twice 10.1 and twice 10.3, on two different serial numbers.

Now I have a new PC where I would like to install Delphi CE, but as the subject says, I get a message that the limit is reached.

Does anyone knows what the limit for a specific serial number is? In the FAQ's about Community I found 5 users on the same network.

I flushed an old laptop on which I was running a 10.1 and did a complete reinstallation. Does that add up to a total of 5, blocking the registration on my new PC?

I reported this issue to Support, but they answered that since this is about Community Edition, I should go to this forum.

Who can help here?