Ssl – No Certificates Found on Chrome Android with Comodo Positive SSL and IIS

For software testing reason, I have registered a domain name, set its A record to point to 192.168.1.30 (local PC on my network).
I have installed Comodo Positive SSL for this domain on IIS on Windows 10 on this IP.

I can access mydomain.com under SSL from any external PC browser, within my interal network (I only care for my internal network). The SSL chain is as follows:

However, when I navigate from an Android's Chrome browser, I am getting "No Certificates Found":

If I hit cancel, the page loads as expected with green padlock, and the certificate info is as follows:

The other problem that I am having which I think is connected to this problem is that I have a native Android app that is trying to connect to the website, it is working on port 80 but failing connection on SSL (port 443).

I have tried accessing the domain on SSL from an iPhone but connection times out but it is connecting fine on non-secure.

My questions are:

1 – What is the cause of this problem?

2 – How can I solve it? Please note that I don't want to solve it for a particular Android (I probably could solve this by installing the certificate manually), I want to solve it to all potential users.

I tried navigating to another website ( https://lifetanstic.co.ke/ ) that uses the same certificate chain, I wasn't asked to install any certificate, the padlock appears and the certificate details are the same. So, everything worked fine for that site.

Please note that my host name is pointing to an IP in my network, which means it is only accessible from my local network (and the Android is on my local network). So, could that be a factor to this problem?