Don’t go directly to graph.api – always use one of the other two links. They will redirect you to the correct shard after you login (many details you don’t need to know at FAQ: How to find out what "shard" (cloud slice IDE URL) your Account / Location is on?). If you login to the wrong shard and install a SmartApp or DTH, you won’t see it in your account (and it will be confusing).