plugin uncertain path

Hello,

i’m using the plugin “icegram” for popups. Normally it works great, but on of my one sites i can’t add new popup campaign.
i’ve seen in firefox that just this site to add a new popup is uncertain although i change to https with the plugin “better search and replace”.

Any idea what i can do?

p.s. i tried 2 version to install the plugin. Via FTP and in bei backend