WX5 11 is very old, and does not work on modern (non-deprecated) server systems.

If you are insisting on using v11, then I understand that you will find it on your account pages.

I hope that this helps.

Hello Edyta, 

thank you for getting in touch. 

Please find here the setup for version 11: https://helpcenter.websitex5.com/pl/spolecznosc/uzytkownicy/53714/downloads

Thanks! Kind regards.

***** Google Translation:

Witaj Edyto,

dziękuję za kontakt.

Tutaj znajdziesz konfigurację dla wersji 11: https://helpcenter.websitex5.com/pl/spolecznosc/uzytkownicy/53714/downloads

Dziękuję! Z poważaniem.