I deployed a SharePoint Hosted App.
When I use my App in my site through HTTPS, the browser (IE11) gives me the warning
only secure content is displayed
How can I undestand which content in my App is not secure?
What is causing the problem should be visible in your console, hit F12 to see developer tools, in your IE console you should see something like "SEC7111: HTTPS security is compromised by..." with the link to your insecure content.
You can also use other developer tools, such as Chrome developer tools, which will state something like "[blocked] The page at ... ran insecure content from ...".