How Can I Remove the SSL Warning?

I’ve installed GitLab CE using the omnibus package on CentOS 7 and then enabled HTTPS. However, whenever I visit my GitLab site I get a warning in Firefox that unsecured parts of the page have been blocked. It seems as though some images or assets are being delivered over HTTP instead of HTTPS. This error seems to be present on too not just my local installation. Below is a screenshot of the SSL warning I get in Firefox:

Any ideas how to fix this problem? Thanks!

I cannot reproduce it. Can you pin-point which images are causing this issue? From the green lock you can go to Information and then choose the Media tab.

It only occurs using Firefox on Mac so if you have access to a Mac with Firefox you can reproduce it. If I review the images under the media tab they are all HTTPS.