Mixed content issues are issues with your HTML, not your server or certificate setup. @schoen linked to some great resources yesterday:
According to whynopadlock.com you have two references in your HTML that are preventing your padlock from appearing:
Hard Failure
A file with an insecure url of "http://jsonip.com/" was loaded via the javascript file: https://tendernotice.com.np/js/jquery.js?_debugResources=y&n=1529782093954 on line 2582. The insecure URL may not be directly contained in the script file and may exist elsewhere.
You may need to contact your web hosting provider for assistance.
This URL will need to be updated to use a secure URL for your padlock to return.
An image with an insecure url of "Latest 2025 Index Tenders In India | Tender Tiger Neo" was loaded on line: 1071 of https://tendernotice.com.np/.
This URL will need to be updated to use a secure URL for your padlock to return.
https://www.whynopadlock.com/results/61512708-918e-42b8-8499-2555be4efd49