Why is it that when I'm visiting my WHM Hostname URL, it's getting an unsecured red lock?
Likely, the hostname was recently set up, and you had a placeholder set for your hostname. When the cPanel & WHM are installed on your server, the AutoSSL feature runs for your current Services. It establishes an SSL certificate to the current hostname. Here is an example;
Adam-Saads-MBA:~ adamsaad$ curl -ILv https://server.example.com:2087
* Rebuilt URL to: https://server.example.com:2087/
* Trying IP Address...
* TCP_NODELAY set
* Connected to server1.peramix.com (IP Address) port 2087 (#0)
* Server certificate:
* subject: CN=*.cprapid.com
* start date: Jun 28 00:00:00 2021 GMT
* expire date: Jun 28 23:59:59 2022 GMT
* subjectAltName does not match server.example.com
* SSL: no alternative certificate subject name matches target host name 'server.example.com'
* stopped the pause stream!
* Closing connection 0
* TLSv1.2 (OUT), TLS alert, Client hello (1):
curl: (51) SSL: no alternative certificate subject name matches target host name 'server.example.com'
We can see from the example that no alternative certificate subject name matches the target hostname 'server.example.com' since the certificate was issued to "*.cprapid.com," the place holder.
You can follow this guide to request a new Service SSL Certificate for your hostname:
How to generate a free hostname certificate with AutoSSL