Algebra 2 Asymptote Lines Graph Problems

I'm having a tremendous amount of problems moving asymptote lines in the Algebra 2 course.  You are supposed to click-and-drag them but it is just not working. I've tried Microsoft Edge, Chrome, and Firefox and they all do the same thing. I got it to work once but haven't ever been able to do it again... and that's leadng to me missing problems and not being able to make progress anymore.  It is happening in the mastery challenges of the graphing logrithmic functions section.