What file name I have not tried! English letters only. What models have I tried. Downloaded from grabkada and singivers. None of this trial simulink opens! Why is this 2020 version. Is it necessary then if it is not really capable of opening any format? Dozens of files and of different formats have the same error - invalid file name. And I don't have a dot at the end of the file name! It only appears in the error message.
The File Solid can read Parasolid files, which typically have the extension x_t. Perhaps the file you have is invalid. Did you try opening the same file in CAD software. I'm happy to help with more information.