Hello Danielle,
I am sorry to hear that you have encountered this issue with loading your handout.
This is a known issue that can occasionally occur if the handout is loaded too soon after the initial launching of the game. The devs are aware of this issue and are still investigating the root cause so we can prevent it in the future.
However, to attempt to restore this handout, it will require a Roll Back. As a Pro subscriber, you have the ability to Roll Back your game to before you encountered this issue as long as it has been within the past 7 days.
If you have any issues trying to do this Roll Back yourself, please let us know the name of the campaign and handout, as well as when you first noticed this issue, and we will be able to provide additional assistance.
Thanks!