Trados 2021 with subtitle plugin crashes constantly with no error message

Dear Community, 

I hope someone can help. I have downloaded and installed the Trados 2021 subtitle plugin plus filetype plugin for srt files. I have created a  new project and included the mp4-video file and srt file (with matching file names except for the ending). So far, so good.

When I open in the SRT file in the editor and click on "Subtitle Preview", it seems to load the video and I can see a still image of it at the bottom of my screen - but then, the system unvariably crashes without an error message, it just goes grey and dies on me. 

I have restarted the computer and Studio several times, to no avail.

Help! I need to subtitle several hours of video material and had relied on the plugin working.... Can anyone tell me what might be causing this??

Best!

Silvia

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