Trust additional CAs and make use of the Android certificate store in a net6 MAUI solution-CodePudding

System.Net.WebException: 
java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.'

This is an error that occurs in my VS2022 solution when working with a self signed certificate and Android.

The case is the following:
It is an android app that runs on an local network, with a local https backend service. A certificate has been issued for this service by the domain admin. However, the domain is not an official CA (Certificate Authority). You then have to manually install a CA, via settings.

Part of the solution
What I did to solve this is adding the CA certificates to the Android device (via Settings > Security -> Encryption & Credentials -> Install a Certificate).

The web browser, in the android app, can now successfully access the https site, without warnings.

I still need help with
However the CA store is not accessible via the app unless it is configured via network-security-config:

Add a network_security_config.xml file, under the Android folder, with:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config>
        <trust-anchors>
        <!-- Trust preinstalled CAs -->
        <certificates src="system" />
        <!-- Additionaly trusted user added CAs -->
        <certificates src="user"/>
    </trust-anchors>
    </base-config>
</network-security-config>

And in your AndroidManifest.xml add the: android:networkSecurityConfig="@xml/network_security_config" attribute to your Application node.
So, add it to the already existing node, don't add a new one (or else you'll get strange errors):

And the error is gone, but I'm still curious if there is another way - without the network-security-config. ;-)