I'm also experiencing this issue, specifically with delayed Amazon
orders. If I purchase a label for a couple days out, when that day
comes, it's only Amazon orders that get the failure to notify error.
Amazon actually makes this difficult. For whatever reason they do not
make custom/personalized item information available via their API, which
means integrations like ShipStation cannot access it, not without
implementing some workarounds.
I also needed a fix for this, so as a computer programmer I developed a
solution which I now offer to others via my software company BlueWare
Labs. This is an alternative to Data Automation's solution. You can
learn more about my solution here: