Invalid Intermediate error in SSL certificate

[Sam4829]

My domain is: https://www.homepacexpress.com

I ran this command: SSL test

It produced this output: Test Results: www.homepacexpress.com - Why No Padlock?

My web server is (include version): Nginx

The operating system my web server runs on is (include version): Ubuntu

My hosting provider, if applicable, is:

I can login to a root shell on my machine (yes or no, or I don't know): yes

I'm using a control panel to manage my site (no, or provide the name and version of the control panel): no

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):

[rg305]

Hi @Sam4829 and welcome to the LE community forum

It seems that Why No Padlock? isn't handling the LE default chain as expected.
That result is being shown by them for all sites that use that chain - including their own site:
Processing Test - Why No Padlock?