After the installation of SSL and forced HTTPS protocol, mixed content's issue can appear on the website. This displays "Not fully secure" warning next to domain in URL bar.
Mixed content means that you are trying to load images or other content with HTTP in their links, to fix this, you would simply need edit all the links on your page to have HTTPS at the beginning instead.
You can see the list of these links by right-clicking anywhere on your website, selecting inspect element and going to the Console tab. HERE is how you can do it on different browsers.
You can also use this website to identify the content that's causing this issues: whynopadlock.com
When you see what causes the issue, the installation of a plugin Really Simple SSL can fix it automatically:
- Log in to your WordPress dashboard and click on Plugins > Add New
- Install and activate a plugin named "Really Simple SSL"
- Click on Settings > General
- Change the address of your blog from http:// to https://
You can use another plugin called "Search&Replace"
- Once you install the plugin press on Tools and Search&Replace.
- To "Search for" field enter the domain's name with http, for example htttp://domain-name.com
- To "Replace with" field enter the domain's name with https, for example htttps://domain-name.com
- Tick Select all the tables, untick Dry Run and press button "Do Search/ Replace"
That's all! You are good to go and should have your website displayed as Secure now!