Click on it!
But not sure why yours has a red line though it, mine is just the plain lock.
A slash through the padlock, the https, or the https appearing in red all mean one thing: something's wrong. ... Https, which stands for secure http, is used instead of http to do two things: confirm the identity of the site you're connecting to, and keep your communications with that site secure by encrypting it all".
If you are Firefox it means the "connection between Firefox and the website is either delivered using an insecure protocol ( HTTP) or that it is only partially encrypted because you've manually deactivated mixed content blocking."