Is it a wordpress website that you are having issues ? generally such error occurs when you have mentioned images path with URL e.g. http://abc.sc/image/1.png now this source is not secured .. so you have make that link secured so that will change the link to https://abc.sc/image/1.png .. if its a wordpress site then install plugins like simple SSL and that will fix the issue.
The main issue when you switch from http to https is the mixed content. Because you can't load any assets or images under http when you want to use https. So use chrome to check what are the issues with right-click > Inspect.
In the console you should see if there are content loaded under http.
Ensure that all the resources of your website (images, videos, scripts) are hosted locally on your server, or externally under the HTTPS protocol. Once there are resources that use http:// the website is not fully secure.
Definitely this is due to http has been left in source code instead of https for some link. Please check and review the source code carefully. also you can google to detect this issue, many tools available to detect such issues.
Based on the issues your having, I presume you built your site without SSL, then added it afterwards, correct?
If so, it might be worth checking style sheets if it's a HTML site, especially if you use services such as Google fonts, as the standard links aren't encrypted, therefore your site will show as not fully secured.
If your using a content management system and/or have done the above checks and changes as needed, it might be worth checking your site against one of the bellow services to find the culprit of the insecure site warning.
This will fix all the mixed content issue. You will see full SSL working after doing this.
Note: Backup you db and files before doing this, if you are newbie this is must, or else if anything goes wrong, you may break your website. So take backup first and try this. This will work, as we do it everytime when switching websites built using http to https.
Your website have some link which not secure. To make a website secure , all url in the source code should be secure. If you are using wordpress , then you may use "SSL Insecure Content Fixer" plugin or Really Simple SSL plugin to fix the issue.
You can check SSL is correctly installed on the SSL checker https://www.sslshopper.com/ssl-checker.html If it shows that SSL is correctly installed, you should check that if you have used any image URL or other URL without Https in your website pages. If it is wordpress website, please check all image url used with https://
It may be that some of your link is not secure or does not use https request. Search source code & check any link which doesn't contain https, correct those & your website will load with full https. If you use wordpress, there is plugin to fix this issue.