A warning mark on the websites (Inc. this)

[abbasi]

Hi guys,

I think it's nowadays that I see some mark warning the users on websites (next to the name of the website on the address bar) even this one. Please have a look at this screenshot to see the issue.
What is the problem please and how to solve it?

 

[EndlessWaves]

I believe this is now normal behaviour for chrome.

 

[abbasi]

But there are some sites that there is no such marks on them! Do you have such behavior on your chrome as well?