Facing Error while integrating a start process web api

When you get a 500 Internal Server Error while calling the Web API from the integration object, it means the issue isn't with authentication but with how the Web API is handling the request.

Here are some possible reasons for the error:

• The data you're sending from the integration (like query parameters, headers, or the request body) might be different from what you tested in Postman. Make sure everything matches exactly, including required fields, formats, and values.
• The integration might be sending null or unexpected values that the Web API isn't able to handle properly.
• Check the Web API logic for any unhandled errors, like missing checks for null values, divide-by-zero errors, or issues with data validation.

Hello adityapavan 
You might need to re-verify the payload structure that you have used here and the one in Postman. Check if there is any difference. Could you also post the Appian Payload request.