After installing of wine-6.0-rc1:
[13/12/2020 11:38:43] [ERROR] Backend system refused server! Check your AuthKey
Which means: I have to downgrade the installed version of wine on my machine…
Now it’s obviously clear why the key cannot be accepted.
If somebody had maybe similar issue and can provide solution, pls share.
If not - then I guess this case / issue can be put “ad acta”.