Meteor always connect to local MongoDB

I have a MongoDB cluster with replica enabled, my MONGO_URL looks like the following:

mongodb://algohub:<password>@algohub-shard-00-00-vwc3c.mongodb.net:27017,algohub-shard-00-01-vwc3c.mongodb.net:27017,algohub-shard-00-02-vwc3c.mongodb.net:27017/<dbname>?ssl=true&replicaSet=AlgoHub-shard-0&authSource=admin

It seems Meteor 1.4 can not recognize this URL, thus it always launches a local MongoDB.

How are you setting your MONGO_URL?

environment variable, for example export MONGO_URL="mongodb://xxx"

However, I deleted node_modules and re-installed everything, then there is no issue anymore