Editor error - it doesn't open the project for translation

I cannot open a file for translation, Editor view doesn't open.
It shows me an Error window with information:
"Unexpected exception when initializing view part Fragment Matches."

When I click Files and try to open the project for translation, all other functions freeze and stop working.

What should I do to fix it? I use SDL Trados Studio 2019 SR2

Thank you.
Alex