GraphQL API - Error message "Self signed certificate in certificate chain"

[loknathbaskar]

https://payments.sandbox.braintree-api.com/graphql

We are calling the Braintree GraphQL API endpoint, which returns the Self signed certificate message. It works fine when we call from a local machine, but we get this message when we test with postman or our SIT AKS environment.

I tried adding the SSL certificates listed below but had no luck.
https://developer.paypal.com/braintree/docs/reference/general/best-practices/ruby#tls-certificates

Any advice or information on how to resolve this issue would be greatly appreciated.

Please do let me know if any other additional information is required.