diff --git a/lib/server.js b/lib/server.js
index 0a9a703..d30bedd 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -2448,7 +2448,7 @@ WalletService.prototype._normalizeTxHistory = function(txs) {
   });
 };
 
-WalletService._cachedBlockheight;
+WalletService._cachedBlockheight = {};
 WalletService._clearBlockchainHeightCache = function() {
   WalletService._cachedBlockheight.current = null;
 };
@@ -2457,7 +2457,6 @@ WalletService.prototype._getBlockchainHeight = function(network, cb) {
   var self = this;
 
   var now = Date.now();
-  if (!WalletService._cachedBlockheight) WalletService._cachedBlockheight = {};
   var cache = WalletService._cachedBlockheight;
 
   function fetchFromBlockchain(cb) {