SSRS redirecting https to http

Hello, recently we upgraded SQL Server 2005 to SQL Server 2008R2 along with SSRS. for database side every thing is running but from SSRS end there was an issue. when i am accessing the url https://callreports.ap.airtel.com/Reports then it was working fine when i open a report and go to properties and click on subscriptions or datasources or parameters or processing options or report history then it will redirect to http as http://sqlreports.gi.telenor.com/Reports/Pages/... and displays error internet explorer can not display the webpage. when i add "s" to the http and run https again it works and subscriptions parameters every thing works. now i am confused why this is happening network team says it needs to be resolved from application end. i configured SSRS with valid SSL certificate removed http every thing i tried but no luck. please share your views to help me from this issue.