Mail send error if SMTP connection reset
See this discussion: https://mail.ow2.org/wws/arc/lemonldap-ng-users/2020-01/msg00062.html
There is a cache for SMTP connection, in lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Lib/SMTP.pm
our $transport;
has transport => (
is => 'rw',
lazy => 1,
default => sub {
return $transport if $transport;
...
Commenting the "return" line seems to fix the issue, but maybe we can find a better way to test connection before using it.