diff --git a/src/vs/base/common/network.ts b/src/vs/base/common/network.ts
index 70093426625bc35ada01c432221f142657e5a090..6d41e85e42b1a0dfe2272ac444f75d561d83301b 100644
--- a/src/vs/base/common/network.ts
+++ b/src/vs/base/common/network.ts
@@ -93,7 +93,7 @@ class RemoteAuthoritiesImpl {
 		}
 		const authority = uri.authority;
 		let host = this._hosts[authority];
-		if (host.indexOf(':') !== -1) {
+		if (host && host.indexOf(':') !== -1) {
 			host = `[${host}]`;
 		}
 		const port = this._ports[authority];