Hi @aartimhatre40,
I'm sorry to hear that you're running into issues while testing in the Sandbox environment. There a community that is especially geared toward discussion of solutions to issues with integration. Please take a look at the Merchant Integration Technical Support Community. You may find the answer to your question already posted there. If not, you can make a new post with your question for the community to answer.
I hope this helps!
Olivia
... View more