Certificate error

I just built myself a new computer and when I sign into the league of legends client I get a security alert stating, "This page requires a secure connection which includes server authentication" (please note that the security alert only pops up when I sign into the client not when I open the client"

This alert doesn't prevent me from playing league of legends it's just getting irritating to close it all the time. Is there any way to stop this alert from popping up every time is sign into league?