Getting certificate errors on webview browsers, while standalone browsers work flawless

Hi,

I'm getting an error message: "Certificate authority is not trusted." while using webview browsers.

On "standalone" browsers like Mull or Cromite I don't have this error.

Specs:
Android 10
Free Browser v2.8
Mulch Webview v126.0.6478.110
AdAway (root) v6.1.1 with installed certificate
Root with Magisk v27.0
Modules: Systemless Hosts
                  Magisk Trust User Certs
                  Open Webview
Private DNS: unfiltered.adguard-dns.com

Anybody knows how to fix this?