Android Chrome "Your connection to this site is not private"

I am using Letsencrypt with Nodejs + Express in AWS. I used this package to generate ssl certs.

The problem is that , the site runs fine on Chrome Desktop browser, however on Android Chrome there seems to be an error. The site loads, but there is a red lock icon in the address bar. I looked at similar configurations from other threads. I did use fullchain.pem and privkey.pem as the configuration. Am I doing something wrong? Any help is greatly appreciated. Thanks !

SSL Labs -

The error states there that the page includes elements which are not secure. i.e within your page you include elements via http