CentOS - Feb 2017 - Amavisd-new DKIM query timeout

Hi,

amavisd is adding the following header to my mails :

Authentication-Results: my.example.com (amavisd-new); dkim=neutral
reason="invalid (public key: DNS query timeout for
their._domainkey.example.com)" header.d=example.com

The problem is that this is not quite true !

I have no DNS problems, e.g. if I do :

dig their._domainkey.example.com TXT

dig returns fine without any substantial wait.

What setting am I missing ? Where am I going wrong ?


Thanks  !

Tim