IPA-EPN: Fix SMTP connection error handling
Enhance error message when SMTP is down.
Fixes: https://pagure.io/freeipa/issue/8445
Signed-off-by: François Cami <fcami@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>