diff --git a/src/handlers/fix-request-body.ts b/src/handlers/fix-request-body.ts
index 40c6c9e4..cc9d2776 100644
--- a/src/handlers/fix-request-body.ts
+++ b/src/handlers/fix-request-body.ts
@@ -17,7 +17,7 @@ export function fixRequestBody(proxyReq: ClientRequest, req: Request): void {
     proxyReq.write(bodyData);
   };
 
-  if (contentType.includes('application/json')) {
+  if (contentType && contentType.includes('application/json')) {
     writeBody(JSON.stringify(req.body));
   }