Fully Secure Backend but warning on the FrontEnd

Hello Simple SSL,

Thank you for making this most awesome plugin.

I just installed an SSL and the Simple SSL Plugin.

When I login to my WP Dashboard in the back end,
The HTTPS appears green and Chrome adds the Green Lock Icon, with the word “Secure” al in green…

When the same site is viewed from the Front end, the Green elements disappear and the ! grey icon appears instead.

This is what it reads if clicked:

“Your connection to this site is not fully secure
Attackers might be able to see the images you’re looking at on this site and trick you by modifying them.”

Could you please advise me in this matter?
I would be happy to let you know the URL and even grant you access privately.

Thank you so much!