diff --git a/plugins/qmail_deliverable b/plugins/qmail_deliverable
index 0704b06..b22d221 100755
--- a/plugins/qmail_deliverable
+++ b/plugins/qmail_deliverable
@@ -77,7 +77,7 @@ sub register {
         $self->log(LOGWARN, "Odd number of arguments, using default config");
     } else {
         my %args = @args;
-        if ($args{server} =~ /^smtproutes:/) {
+        if ($args{server} && $args{server} =~ /^smtproutes:/) {
 
             my ($fallback, $port) = $args{server} =~ /:(?:(.*?):?)(\d+)/;