diff --git a/src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetric.java b/src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetric.java
index 1fd6ef5..8a92fa0 100644
--- a/src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetric.java
+++ b/src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetric.java
@@ -199,7 +199,7 @@ private void parseHeadersAsJsonProps(boolean allReqHeaders, boolean allResHeader
                 String[] header = lines[i].split(":");
 
                 // if not all req headers and header contains special X-tag
-                if(header.length > 0) {
+                if(header.length > 1) {
                     if(!this.allReqHeaders && header[0].startsWith("X-es-backend")) {
                         this.json.put(header[0].replaceAll("es-", "").trim(), header[1].trim());
                     } else {