public-inbox-nntpd | 3 +--

diff --git a/public-inbox-nntpd b/public-inbox-nntpd
index 70bab46f304bc121ef1bf62b570665f79c0a669d..9fb69cec67ef7bc8544aea3c195503d1e4cd0453 100644
--- a/public-inbox-nntpd
+++ b/public-inbox-nntpd
@@ -204,8 +204,7 @@ 		my ($dmap, undef) = @_;
 		my $n = 0;
 
 		foreach my $s (values %$dmap) {
-			next unless ref($s) eq 'PublicInbox::NNTP';
-			if ($s->busy) {
+			if ($s->can('busy') && $s->busy) {
 				++$n;
 			} else {
 				$s->close;