The site Phonel.ir uses a SSL certificate. Why is the Error message in red? Is there a problem with the SSL certification?
I sometimes use a proxy. Can that be the reason?
Some parts of the webpage (for example images) are loaded using a insecure connection. This parts could be changed by a MitM attacker without you noticing it. You can use a service like whynopadlock.com or the developer tools of your browser to find out what exactly causes this!
In this specific case, three images are included using a unencrypted http connection!
Sometimes website developer embed scripts or images from other Websites like bootstrap or somthing else. If they do that they forget to call this scripts with a SSL connection to this site. So if they do so, the SSL/TLS Certificate is set up the right way but they call unsecure content which can be intercepted. That's why the triangle may be there. You can get more information about that behavior from here