Autoblog HTTPS Mixed content issue.

I am fetching news using Autoblog but from the source, I am fetching the news is using http:// and my website is https://.

So when the user clicked Click here to read more iframe pops up but with no content and it is because of iframe content is coming from a non-https site https://monosnap.com/file/aA18yA9twVGQajmgxONPRg8Y0DJdli And the browser blocked the content: https://monosnap.com/file/odbLBtPY1bsyh6210KzsvecV4Yu1Td

How can we solve this issue? Please help.