DNS blacklisting overrides server-wide white list, however, opposite is stated in documentation.
Qmail mail service is installed on a server.
This behavior has been confirmed as software issue with ID #PPPM-1172 .
It will be fixed in future product updates.
Currently, there are two possible workarounds:
- Switch MTA to Postfix according to the KB article:
- Disable DNS RBL protection on a server.