I think you are violating browser's same-origin policy. Check CORS specification for more details. If Pega and the other application are in different domains, you need to enable CORS via access control policy headers.
Hi , Thanks for the reply. if that is the case it should not work from portal level it self. but postmessage to different origin is working successfully from portal. But not from any other screens inside portal.
where can i enable CORS via access control policy headers? Pega DSS CORS allowedorigins in my application is '*', which is accept request from all origins. further in my case i am not listening to request, but posting message to other application.