520 Error on all splash requests

I've setup splash through docker on Windows 10.

The first page loaded through the UI renders fine. But subsequent requests or requests through a python script bring up a 520 error, 'Render is cancelled' message after timing out.

2021-06-05 11:46:45+0000 [-] Log opened.
2021-06-05 11:46:46.136864 [-] Xvfb is started: ['Xvfb', ':1106034356', '-screen', '0', '1024x768x24', '-nolisten', 'tcp']
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-splash'
2021-06-05 11:46:47.810197 [-] Splash version: 3.5
2021-06-05 11:46:51.208622 [-] Qt 5.14.1, PyQt 5.14.2, WebKit 602.1, Chromium 77.0.3865.129, sip 4.19.22, Twisted 19.7.0, Lua 5.2
2021-06-05 11:46:51.271032 [-] Python 3.6.9 (default, Jul 17 2020, 12:50:27) [GCC 8.4.0]
2021-06-05 11:46:51.274762 [-] Open files limit: 1048576
2021-06-05 11:46:51.275080 [-] Can't bump open files limit
2021-06-05 11:46:52.255744 [-] proxy profiles support is enabled, proxy profiles path: /etc/splash/proxy-profiles
2021-06-05 11:46:52.258866 [-] memory cache: enabled, private mode: enabled, js cross-domain access: disabled
2021-06-05 11:46:55.428843 [-] verbosity=1, slots=20, argument_cache_max_entries=500, max-timeout=90.0
2021-06-05 11:46:55.430550 [-] Web UI: enabled, Lua: enabled (sandbox: enabled), Webkit: enabled, Chromium: enabled
2021-06-05 11:46:55.436579 [-] Site starting on 8050
2021-06-05 11:46:55.436865 [-] Starting factory <twisted.web.server.Site object at 0x7f62482c25c0>
2021-06-05 11:46:55.446583 [-] Server listening on http://0.0.0.0:8050
QNetworkReplyImplPrivate::error: Internal problem, this method must only be called once.
2021-06-05 13:06:56.816942 [events] {"path": "/render.html", "rendertime": 17.658066034317017, "maxrss": 66184, "load": [52.78, 34.1, 17.32], "fds": 52, "active": 0, "qsize": 0, "_id": 139634488478072, "method": "POST", "timestamp": 1622898416, "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36", "args": {"headers": {"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8", "Accept-Language": "en", "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36"}, "url": "https://www.google.com/", "uid": 139634488478072}, "status_code": 520, "client_ip": "172.17.0.1", "error": {"error": 520, "type": "CancelledError", "description": "Render is cancelled", "info": {"remaining": 26.667580366134644}}}
2021-06-05 13:07:09.297256 [-] Timing out client: IPv4Address(type='TCP', host='172.17.0.1', port=42364)

scrapinghub / splash

520 Error on all splash requests #1124