diff --git a/src/net.ts b/src/net.ts
index a3cd12d..6ca2d69 100644
--- a/src/net.ts
+++ b/src/net.ts
@@ -55,18 +55,18 @@ export const signedFetch = async (url: string, init: RequestInit, signedInit: Si
         headers: signedHeaders
     });
 
-    const newHeaders = new Headers(
+    const newHeaders: HeadersInit = 
         [
             ...signedHeaders,
             ["Signature", signature],
             ["Content-Type", `application/ld+json; profile="${CONTEXT}"`]
         ]
-    );
+    ;
 
     if (Array.isArray(init.headers))
         init.headers
             .filter((header) => Array.isArray(header))
-            .forEach(([key, value]) => newHeaders.set(key, value));
+            .forEach(([key, value]) => newHeaders.push([key, value]));
 
     console.log("Headers:");
     for (const [key, value] of newHeaders) {