Fetch does not work on Android 9 with SDK 28

How-to Discussions
6

Yep, its the SSL(https) connections in Pie, it looks like you can specify non-secure domains for “clear text traffic” through adding Network Security Config to your manifest:

<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">insecure.example.com</domain>
        <domain includeSubdomains="true">insecure.cdn.example.com</domain>
    </domain-config>
</network-security-config>

Manifest Ref: Add values to AndroidManifest?