Strangely it is working on all devices except the device through which I installed the SSL certificate. I tried clearing all the cache, checked in different browsers, and also restarted the system, but still the same error!!
Could you please try checking the site in Incognito Mode? I know that Google Chrome, and possibly derivatives, keep an SSL cache. And clearing the browser cache does NOT clear this certificate cache. The only way to completely bypass all browser caches is with Incognito Mode.