the problem here is not the banks or apps, the problem is Google Play Integrity API, which is supposed to enforce to run apps in secured phones and it is used to ban secured ROMs such as GrapheneOS and it allows to run apps on outdated phones without security patches.
I feel that sometimes resolution of sub-domain.duckdns.org and host.sub-domain.duckdns.org fails with empty result or even timeout result. Tested resolution against Google and Cloudfare DNS servers.
the problem here is not the banks or apps, the problem is Google Play Integrity API, which is supposed to enforce to run apps in secured phones and it is used to ban secured ROMs such as GrapheneOS and it allows to run apps on outdated phones without security patches.