diff --git a/lib/platform/azure/index.ts b/lib/platform/azure/index.ts
index cbd92020803d071b8b7366016c0fb6351d3a7677..9cbc7d690b6cb132871f86f0c3edab9095bac7cf 100644
--- a/lib/platform/azure/index.ts
+++ b/lib/platform/azure/index.ts
@@ -512,7 +512,7 @@ export async function ensureComment({
   threads.forEach(thread => {
     const firstCommentContent = thread.comments[0].content;
     if (
-      (topic && firstCommentContent.startsWith(header)) ||
+      (topic && firstCommentContent?.startsWith(header)) ||
       (!topic && firstCommentContent === body)
     ) {
       threadIdFound = thread.id;