Order REST API version 2021-04 creates orders and returns 500 Internal Server Error

[HarryX]

Hello

REST Admin API version 2021-04 is used.

The Create Order API does the job and creates orders. However, it returns 500 Internal Server Error for lots of orders. One store had this problem before. And the return becomes normal since 5/21. Several days ago, another store started to have the same issue.

Thanks