diff --git a/Koha/AdditionalField.pm b/Koha/AdditionalField.pm
index e3b675bc62..25d6808c16 100644
--- a/Koha/AdditionalField.pm
+++ b/Koha/AdditionalField.pm
@@ -62,7 +62,7 @@ sub to_api {
 
     my $json = $self->SUPER::to_api($params);
 
-    $json->{resource_type} = $table_to_resource->{ $self->tablename };
+    $json->{resource_type} = $table_to_resource->{ $self->tablename } || $self->tablename;
 
     return $json;
 }