Why has my custom app stopped sending data to Litmos?

I’ve got it working! We found this page: https://litmoscorp.my.site.com/customerportal/s/login/?ec=302&startURL=%2Fcustomerportal%2Fs%2Farticle%2FWhy-arent-my-Shopify-users-getting-created-in-Litmos

On it there were some instructions that we followed and got things connected. Two main things that we changed were the Last Order ID and the API Password. The instructions did clarify a few items that got it up and running.