Bug "Machine identification is invalid for current license" Error

Hello!

I am a long-term trusted Unity user. I wanted to try out Unity again and still have a deja-vu feeling I posted about this, but cannot find my post at all. So here's the thing.

I started Unity Hub to create a new project, but was welcomed with "Machine identification is invalid for current license. Double-checking I noticed that I don't have a license activated. So I tried "Activate new license" and went through activating a personal license. Now I got "Your license successfully activated" followed with the machine identification error. So after some digging people reported that I should pick manual activation, enter my MAC-address in the file, and activate it that way.

Said and done, I can now see my license, so I download Unity and start a new project. Works without issues. However, when I close Unity and start it again, I am welcomed by the same error, and cannot seem to do the same workaround as before. This now prevents me in all ways from using Unity. So at this time, I tried;

* The same activation procedure as done above.
* Uninstalling VPN services and software.
* Uninstalling / Reinstalling Unity & Unity hub.
* Using different DNS.
* Using different accounts.
* Disabling antivirus.
* Running as admin.
* Performed the "Troubleshooting" steps, to no avail.
* And finally, basically restarted my computer in between every first 5 steps above.

Nothing seems to start Unity from this point. And I am just a casual user, following every basic step just to get it working. Many people seem to have had issues come and go with Unity Hub / licensing service.

What else is there to try?

EDIT (Potential fix): I found something that might have worked. This fix has been tested with multiple restarts of Unity Hub, restart of the computer, and still I can open the project fine (so far). It involves the manual activation method, but make sure that the letters in the MAC-address is lower-case. If they are upper-case (like the standard in ipconfig, also don't forget the colons instead of dashes), Unity will launch once, and not work upon reopening the project. Putting lower-case letters instead (for some strange reason) made it work for me. If I stumble upon more issues, I will repost here.