Checking if site is ready for force https?

Sorry for the newbie question. I run a small forum for invited people, but the site is blocked by some “cisco umbrella security”, which I think might be because I haven’t forced https. I think the site is ready for it. Here is a screenshot from the security page in chrome.

The warning is: Mixed Content: The page at ‘’ was loaded over HTTPS, but requested an insecure image ‘’. This content should also be served over HTTPS.

The install is more or less just the default, I have not uploaded any logos on my own. Am i right to assume that if i manually upload “logo small” on the admin control panel, the site should be ready for force_https?

If it’s a standard install then force_https is perfectly safe.

Turn it on, worst case you disable it from the rails console.