The WorldServer components that you have installed do not match your Studio version. The components for your Trados Studio version are not available on the RWS store. Please follow these steps:
1- Close Trados Studio 2021 SR2 - 16.2.12.9338
2- Download the attached zip file "Studio2021 CU4 and below (16.2.1739).zip". You can find it at the end of this article.
3- Once downloaded, unzip it and run the MSI file to install it. The installation will be very fast and silent.
4- Finally, re-open Trados Studio 2021. The Open WorldServer Package button on the Projects page should be available.
5- Open your WSXZ package.
Also, to avoid this situation and be able to find the right WorldServer component for your Trados Studio installation in the RWS store, please consider upgrading to the latest Studio 2022 version and its WorldServer components. See also article:
How to open a WorldServer package (*.WSXZ) in Trados Studio 2021 and 2022
