diff --git a/src/index.ts b/src/index.ts
index 80dd679..58f5cf1 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -294,6 +294,10 @@ class WebTransport implements Transport {
 
     const { url, certhashes, remotePeer } = parseMultiaddr(ma)
 
+    if (certhashes.length === 0) {
+      throw new Error('Expected multiaddr to contain certhashes')
+    }
+
     const wt = new window.WebTransport(`${url}/.well-known/libp2p-webtransport?type=noise`, {
       serverCertificateHashes: certhashes.map(certhash => ({
         algorithm: 'sha-256',
diff --git a/test/browser.ts b/test/browser.ts
index 296102d..ca691fd 100644
--- a/test/browser.ts
+++ b/test/browser.ts
@@ -84,7 +84,7 @@ describe('libp2p-webtransport', () => {
     await node.start()
 
     const err = await expect(node.dial(ma)).to.eventually.be.rejected()
-    expect(err.errors[0].toString()).to.contain('WebTransportError: Opening handshake failed.')
+    expect(err.errors[0].toString()).to.contain('Expected multiaddr to contain certhashes')
 
     await node.stop()
   })