Couldn't connect to integrations from VBCS in staged application.

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I have my VBCS application and we do a service call via service connections which will fetch the data from Integration (service connection created through catalog). This worked fine when I was developing. 

Issue came when I staged the application. I am not able to call this service connection. Getting some error like these: 

Error 502 : A certificate in the remote path is reported as invalid because of 'No trusted certificate found and Sometimes  this : 

URL scheme must be "http" or "https" for CORS request.. When I post in the service connection directly it works. Issue is only when I invoke the same in the application.