Hi @jowilfrid ,
We don't see any issue with the encryption/decryption. Looks like this issue has been sorted out and same for then authentication (two-way ssl + basic auth).
I doubt this is a data related issue. Could you please check if this API is available in your region.
https://developer.visa.com/capabilities/vpp/docs
As this is a sandbox environment, we have provided some test data which can be located under your project. If you're still facing any issue, please write to developer@visa.com. The team should be able to address the data related issues.
Thank you