diff --git a/packages/grpc-js/src/http_proxy.ts b/packages/grpc-js/src/http_proxy.ts
index e24fba2e..2b3fb5d5 100644
--- a/packages/grpc-js/src/http_proxy.ts
+++ b/packages/grpc-js/src/http_proxy.ts
@@ -145,7 +145,7 @@ export function mapProxyName(
     extraOptions['grpc.http_connect_creds'] = proxyInfo.creds;
   }
   return {
-    target: `dns:///${proxyInfo.address}`,
+    target: `dns:${proxyInfo.address}`,
     extraOptions: extraOptions,
   };
 }
diff --git a/packages/grpc-js/src/resolver-dns.ts b/packages/grpc-js/src/resolver-dns.ts
index 1f72f80b..24aa0236 100644
--- a/packages/grpc-js/src/resolver-dns.ts
+++ b/packages/grpc-js/src/resolver-dns.ts
@@ -171,7 +171,15 @@ class DnsResolver implements Resolver {
       });
       return;
     }
-    if (this.dnsHostname !== null) {
+    if (this.dnsHostname === null) {
+      setImmediate(() => {
+        this.listener.onError({
+          code: Status.UNAVAILABLE,
+          details: `Failed to parse DNS address ${this.target}`,
+          metadata: new Metadata(),
+        });
+      });
+    } else {
       /* We clear out latestLookupResult here to ensure that it contains the
        * latest result since the last time we started resolving. That way, the
        * TXT resolution handler can use it, but only if it finishes second. We