# ParaViewWeb, Python Launcher, and Apache, and 'Process did not properly start' Error

**URL:** https://discourse.paraview.org/t/paraviewweb-python-launcher-and-apache-and-process-did-not-properly-start-error/6098
**Category:** Web Support
**Created:** [December 19, 2020, 1:18am UTC](https://discourse.paraview.org/t/paraviewweb-python-launcher-and-apache-and-process-did-not-properly-start-error/6098 "2020-12-19T01:18:54Z")
**Posts on this page:** 1
**Showing post:** 3

<div class="post-metadata">

### Author: ![mayfielg](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/m/71e660/32.png) [@mayfielg](https://discourse.paraview.org/u/mayfielg)
#### Post date: [February 25, 2021, 12:48am UTC](https://discourse.paraview.org/t/paraviewweb-python-launcher-and-apache-and-process-did-not-properly-start-error/6098/3 "2021-02-25T00:48:00Z")

</div>

Hi there,

Thank you @jourdain for those pointers, it was really helpful to getting a working installation of the launcher running for reference.

I’ve gotten the [demo](https://github.com/Kitware/paraviewweb-demo) of yours running on my system, and it’s working great. (Though I can only see the demo at ‘[www.example.com:9000](http://www.example.com:9000)’ if i add `127.0.0.1 www.example.com` to my `/etc/hosts` file, if that is an indication of some other misconfiguration, that would be good to know, otherwise it appears and operates normally at ‘localhost:9000’.)

I’ve used it as you suggested in [this format](http://kitware.github.io/paraviewweb/docs/container_overview.html) and I can see in my log files that the launcher is starting and apportioning sessions and ports to use:

```auto
2021-02-25 00:32:05,379:INFO:twisted:Site starting on 9000
2021-02-25 00:32:05,380:INFO:twisted:Starting factory <twisted.web.server.Site object at 0x7f67ef7a4240>

```

In the browser a ‘Loading Paraview…’ message for about a minute, before the ‘Server Disconnected’ message again comes up, with either an

```auto
WebSocket connection to 'ws://example.com:9000/proxy?sessionId=7b4ac654-7701-11eb-8dff-0242ac110002&path=ws' failed: Error in connection establishment: net::ERR_NAME_NOT_RESOLVED

```

Or an undetermined ‘503’ error, depending on whether I have `127.0.0.1 example.com` to my `/etc/hosts` file or not (no host file additions → ERR\_NAME\_NOT\_RESOLVED, with host file additions → 503):

```auto
WebSocket connection to 'ws://example.com:9000/proxy?sessionId=2eed1fea-7702-11eb-b174-0242ac110002&path=ws' failed: Error during WebSocket handshake: Unexpected response code: 503

```

And the connection times out:

```auto
2021-02-25 00:42:22,022:INFO:twisted:"127.0.0.1" - - [25/Feb/2021:00:42:21 +0000] "POST /paraview HTTP/1.1" 200 211 "http://localhost:9000/" "..."
2021-02-25 00:43:22,045:INFO:twisted:Timing out client: IPv4Address(type='TCP', host='127.0.0.1', port=42990)

```

As a result, I have been digging deeply into exactly what my app is trying to do that is conflicting with the launcher, since it seems clear the launcher is working as expected. What I have realized is this, my app is designed based on the [RemoteRenderer example](https://kitware.github.io/paraviewweb/examples/RemoteRenderer.html#Using-ParaView-as-server) which, I believe, is calling the wslink server directly rather than using the launcher. I am beginning to think I am running into a collision of wslink servers, or perhaps that the issue is that the launcher has no capacity to override the ‘protocol’ argument as exemplified for a RemoteRenderer.

Is there any documentation or examples on how to reconcile these different approaches? Do you have any suggestions?

Thanks, GM

---

_[View the full topic](https://discourse.paraview.org/t/paraviewweb-python-launcher-and-apache-and-process-did-not-properly-start-error/6098)._