Perhaps you can download a newer version of "Scan Tailor Experimental":
https://github.com/Tulon/scantailor/releases
Yours looks years out of date.
I also think by default Scan Tailor is set to "2x Resolution Enhancement". Your images may be too high resolution and your computer couldn't handle it (not enough RAM, [...]).
Maybe try to find a simpler image, get to the Output step and set
Resolution Enhancement to 1x, and then
Apply To all pages.