First, you need to understand that a Shopify order can only be synced to CJ when:
a. The order is paid.
b. The order is placed within 7 days.
c. The order is unfulfilled on any other platforms.
There are three ways to fix the problem generally:
1. Make sure the order is ready to be synced.
2. Make sure your products are correctly connected.
3. "Sync Store Orders" Manually.
Please find more details here: How to Proceed When Shopify Orders Syncing Failed?