Last week I tried for over an hour to do simulation 3a. I did it step by step at the same time as friend who was doing it on their own computer. Despite us doing the same thing, I never received emails, and so I couldn't receive credit. I eventually gave up on the simulation, but in my class lecture today my professor said that 3b will go off of the work that we did on 3a. She suggested I come here and see if 3a can be fixed on my account.
Sorry you're stuck but there's almost always a pretty easy fix! Don't try to start all over again–not necessary! Don't start undoing stuff and don't uninstall Max's Pitch Package, etc.
There's a 95% chance the same snag/fix is listed & answered in the Help FAQ. Check that first but if you can't find it there, post your problem + a screencap in the proper category below & we'll post a solution back ASAP!