diff --git a/src/HttpServer.cc b/src/HttpServer.cc
index d4ca9969..491890b4 100644
--- a/src/HttpServer.cc
+++ b/src/HttpServer.cc
@@ -710,7 +710,7 @@ int Http2Handler::connection_made() {
 
   ev_timer_start(sessions_->get_loop(), &settings_timerev_);
 
-  if (!nghttp2::ssl::check_http2_requirement(ssl_)) {
+  if (ssl_ && !nghttp2::ssl::check_http2_requirement(ssl_)) {
     terminate_session(NGHTTP2_INADEQUATE_SECURITY);
   }