IoT Cross Partition: CredentialProvider call fails from China region to us-west-2

I am trying to setup my IoT core in us-west-2, and want my IoT device in China region. I am using JITR and my device in China can use Data-ATS endpoint to register the device certificate. But query for the credentials using CredentialProvider endpoint fails.

Things I have tried

• having my IoT core in us-east-1 works. I can register on Data-ATS endpoint and query credentials on CredentialProvider endpoint
• having my IoT core in us-west-2 fails. I can register on Data-ATS endpoint but fails to query credentials on CredentialProvider endpoint.

Would appreciate any help regarding the topic. Thanks