Enabled HTTPS in Kong, Installed SSL properly but still it not working with Postman/ThirdParty apps

I installed an SSL certificate for Kong and exposed port 443 ( changed in config from 8443 to 443). Kong starts without any issues and Domain working fine for GET requests from browsers and for GET/POST Curl requests on https. But when I’m trying to hit the same request from Postman or from ServiceNow (integrating API with ServiceNow) page I’m receiving this error “There was an error connecting to https://testapi..com.”.
The same API when routing request from AWS LB to kong on 443, it is working fine.
Therefore, my query is why API is not working when pointed directly to the kong API Gateway. Can anyone please help me here, what am I missing?
Thank you :slight_smile:
Tried with multiple versions of Kong as well, at present trying to resolve on 1.2.2/2.0.2 version