I was in a similar situation recently and thought I was doing everything right but I had neglected to set the correct number of frames in the simulation window.   It was a dress by Arki too, though not this one.   She does wonderful work so it's highly unlikely that it's the dress that's causing the issue.  

I was also certain I was doing everything correctly and was about to write to her to ask for help when it dawned on me what was wrong.  Arki's tutorial recommended setting the end frame at 45 and since I rarely change the number of frames I forgot to set it at 45 in the cloth room's New Simulation window. And this after playing with dynamic clothing for years :)   Hope it's something like that and you resolve it soon.