Illustrator CC 2018 Windows 10 - Can't log in to my account

Dear Support-Team,

one of our customers still uses the old "Adobe Illustrator CC 2018 (v22.1 64-bit)".

So, I have a desktop-pc with windows 10 professional-edition (64-bit) and different versions of Illustrator.

- Adobe Illustrator CC 2018 (v.22.1 64-bit).

- Adobe Illustrator 2021 (v.25.2.3 64-bit).

Everything works fine!

Now I got a new laptop with windows 10 home-edition (64-bit) and I wanted to install again two different versions:

- Adobe Illustrator 2021 (v25.4.1 64-bit).

- Adobe Illustrator CC 2018 (v.22.1 64-bit).

The installation of Illustrator 2021 worked fine and I can use it without any problems.

For CC 2018 I used the installer that I also used about one year ago on the desktop-pc.

When I started the installer on the new laptop, I got the error-message (I translate it roughly from german):

"Update necessary: Your browser or operating system is not supported anymore".

There was a link on the error-message window, which opened a support-website. I tried to solve the problem, using the "registry-fix", but it did not change anything.

After that I searched the support-forum and found the fix for the installation-problem:

I had to disconnect my internet-connection and start the installer again!

Now both Illustrator-versions are installed on my laptop and are also visible in "Adobe Creative Cloud".

So far so good.

Unfortunately, every time I try to start Illustrator CC 2018, I get the message "Adobe is already activated on two other pcs". But that is not true. One of the activated pcs is this laptop.

When I click on (rougly translated from german) "Disconnect all other pcs in order to connect this pc", I get the frustrating error message again:

"Update necessary: Your browser or operating system is not supported anymore".

What could be the reason for this?

When I installed Illustrator CC 2018 on my desktop-pc rougly one year ago, everything worked fine.

Desktop-pc and laptop use the same win10-version.

The only difference is, that the desktop-pc has win10-professional and the laptop has win10-home edition.

How can I solve this log-in issue?

Thank you very much in advance.

Best Regards,

Fabian Taubitz