Hi Nag ,
Welcome to Microsoft Q&A platform and thanks for posting your question here.
As mentioned earlier, kindly share the error details you are getting when you hit on test connection option in linked service. If you are able to access the API in Postman without using any authorization parameters, it is likely that the API does not require any authentication.
However, if you are getting a connection failure when testing the REST API linked service in Azure Data Factory (ADF), it could be due to a few reasons.
Here are some things you can check:
Make sure that the URL of the API is correct and accessible from the ADF environment.
Check the firewall settings of the API to ensure that the ADF IP address is allowed to access the API. You can find the ADF IP address in the ADF properties.
Verify that the REST API linked service is configured correctly. Make sure that the URL, HTTP method, and request body (if applicable) are set correctly. Also, check the headers and parameters to ensure that they are set correctly.
- If the API requires authentication, make sure that you have provided the correct authentication details in the REST API linked service. You can try using different authentication types (such as Basic or OAuth) to see if that resolves the connection failure.
Hope it helps. Kindly accept the answer if it was helpful. Thankyou.