diff --git a/lib/oxidized/input/http.rb b/lib/oxidized/input/http.rb
index 91857e0aa..ca9a4b5f0 100644
--- a/lib/oxidized/input/http.rb
+++ b/lib/oxidized/input/http.rb
@@ -56,7 +56,7 @@ def get_http(path)
     
       res = make_request(uri, ssl_verify)
     
-      if res.code == '401' && res['www-authenticate'].include?('Digest')
+      if res.code == '401' && res['www-authenticate']&.include?('Digest')
         uri.user = @username
         uri.password = @password
         Oxidized.logger.debug "Server requires Digest authentication"