Has Canvas recently changed their qti format? In the past I could export a quiz that used question groups and import it into Respondus 4. When I do that now I get the error when previewing the file: DynaZip UnZIP error: zip file structure invalid (problem extracting file(s)).
I was able to import a quiz qti that did not have question groups. This is an important feature for us. Many faculty are going back to paper exams because of increased cheating.