I'm sorry you are having all of these problems. I don't currently see others having a problem.
Make sure you are signed onto only one account.
Autocrat will not work with a Team or Shared drive.
Is all of the output going to one folder?
If the school has a workplace account, you should be able to send 1500 emails per day.
I'm thinking that something changed within your system. New security software or something like that.
You might want to try copying the files to your personal account and see if you can create the output for 50 rows. You don't have to send the emails. If possible, run not using the school resources. If it runs fine, then there must be something in the school system.
I'm sorry, I don't have a magic answer for you.