502 Bad Gateway NGINX

For a collection, when I mock an API using the mock server URL, the first API mock example returns 200 OK, but 2nd mock example of 2nd API is returning 502 Bad Gateway NGINX.

Steps

  1. Create a collection of APIs
  2. Mock the collection
  3. Create example of the 1st api in the collection, and customize the request and response as per the need, change the endpoint of this api to point to mock server url. Try the mock example, it returns the customized response.
  4. Create example of 2nd API in the collection like 1st API- and customize the request and response as per the need, change the endpoint of this api to point to mock server url. Try the mock example, it returns 502 Bad Gateway NGINX

Can you please suggest what might be reason for 502 Bad Gateway NGINX error.

Update: Issue is resolved, there was some issue in the postman server.