Timeout on large realms

I tried exporting a realm containing a few thousand users, about 300 groups, and 1000 client roles and the endpoint sends a code 504 with the following body :

```
<html>

<body>
	<h1>504 Gateway Time-out</h1>
	The server didn't respond in time.
</body>

</html>
```

Is there any way to bypass this timeout ?