Prefixes to addresses with 0x before sending.

ui/app/send-v2.js

@@ -597,7 +597,7 @@ SendTransactionScreen.prototype.onSubmit = function (event) {
   event.preventDefault()
   const {
     from: {address: from},
-    to,
+    to: _to,
     amount,
     gasLimit: gas,
     gasPrice,
@@ -616,6 +616,8 @@ SendTransactionScreen.prototype.onSubmit = function (event) {
     return
   }
 
+  const to = ethUtil.addHexPrefix(_to)
+
   this.addToAddressBookIfNew(to, toNickname)
 
   if (editingTransactionId) {