X6 Windows 10 registration

My client use CorelDRAW Graphics Suite X6 and now we change computers to new Win10 computers.

Problem is that I can install X6 well in new computers, but cannot register/ sign in with them.

I know original email and pw, what we use years ago when first time install these programs.

I need to install updates 6.1-6.4 and cannot do it without sign in.

Sign in window open when start X6 program and also when starting 6.1 update, but when write initials (email and pw to it) nothing happen and when try few times it's stuck.

This is very important program to my client and X6 is only option, because Finnish language.

Is there any way to solve this?

I already spend hours with these and no luck.