diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index b1b8f46..541c59f 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -837,7 +837,7 @@
         return NGX_ERROR;
     }
 
-    if (plcf->cache_key.value.len) {
+    if (plcf->cache_key.value.data) {
 
         if (ngx_http_complex_value(r, &plcf->cache_key, key) != NGX_OK) {
             return NGX_ERROR;
@@ -3651,7 +3651,7 @@
 
     value = cf->args->elts;
 
-    if (plcf->cache_key.value.len) {
+    if (plcf->cache_key.value.data) {
         return "is duplicate";
     }