This is the browser coming back to you with this information because you are not running the site (I presume) with an SSL certificate and over HTTPS. The web has switched to being a security concise place so browsers will now warn you if you are on an HTTP website and submitting forms with sensitive information, such as login credentials.
You would need to get with your hosting provider/server administrator and add an SSL certificate to the server. Then follow the instructions below to ensure your community is running over HTTPS:
