diff --git a/main/webserver_settings.h b/main/webserver_settings.h
index 6cb4078..98e5da3 100644
--- a/main/webserver_settings.h
+++ b/main/webserver_settings.h
@@ -79,7 +79,7 @@ typename std::enable_if<
 , bool>::type
 showInputForSetting(std::string_view key, T value, std::string &body)
 {
-    body += fmt::format("<input type=\"text\" name=\"{}{}{}{}\" value=\"{}\" pattern=\"[0-9]{4}\" required />",
+    body += fmt::format("<input type=\"text\" name=\"{}\" value=\"{}{}{}{}\" pattern=\"[0-9]{{4}}\" required />",
                         esphttpdutils::htmlentities(key),
                         value[0],
                         value[1],