GnuPG module fails to fetch public key on public server

Dear community,

I’ve been struggling with the RTIR GnuPG module for quite some times now. Whenever I send a signed mail to the RT, I got this error message on the ticket display page :

“Not possible to check the signature, the reason is missing public key”

The same error goes when I try to send an encrypted message to someone who has published his public key. You would think that the problem comes from networking issues such as : gpg cannot connect to the public key server. But it shouldn’t be the case since the following command runs correctly on the server :

gpg --keyserver-options http-proxy= --keyserver --search-keys

Does anybody had the same issue in the past and figured out how to solve it ?



RT_SiteConfig configuration concerning gpg :

      Enable => 1,
	'passphrase' => 'xxx', 
	'auto-key-locate' => 'keyserver',
	'keyserver' => 'hkp://',
	'no-permission-warning' => undef,
	'trust-model' => 'always',
	'keyserver-options' => 'auto-key-retrieve',
	'keyserver-options' => 'http-proxy=',

Current GnuPG version = 1.4.20
RT version 4.4.2.rc2
And latest version of RTIR plugging