Cause: #
Using secure encryption is highly recommended for many websites (for instance, those taking transactions and collecting sensitive user information.)
However, in many cases, webmasters face technical issues when installing SSL certificates and setting up the HTTP/HTTPS versions of the website. In case you’re using an invalid SSL certificate (ex. untrusted or expired one), most Web browsers will prevent users from visiting your site by showing them an “insecure connection” notification.
If the HTTP and HTTPS versions of your website are not set properly, both of them can get indexed by search engines and cause duplicate content issues that may undermine your website rankings.
How to resolve it: #
Every website should be accessible securely with an HTTPS URL. In order to make sure that you’re always using HTTPS, your website should redirect any request from HTTP to HTTPS.
How to Switch from HTTP to HTTPS:
Acquire & Install an SSL Certificate
Add HTTPS Version to Search Console
Set up 301 redirects
Change All Internal Links
Fix Mixed Content Issues: Mixed content actually means that some resources on your website load through HTTPS, but others load through HTTP.