OGS WFS (Web Feature Service) configured on an ArcGIS Server behind reverse proxy does not work using the internal port 6443 for communication and returns the following error message - "Bad Gateway: The proxy server received an invalid response from an upstream server."
A possible workaround is to disable streaming for the WFS.
To update the service property via JSON, refer to the Disable Streaming property in the ArcGIS REST APIs help topic: Extension types: WFSServer
The option to disable streaming is available in ArcGIS Server Manager as of version 11.1. Here are the steps:
For ArcGIS Enterprise 10.9.x and older versions, add the disableStreaming property to the WFS service properties from the ArcGIS REST admin interface as can be seen below.
Unless the datasets are very large, there should be no significant difference by disabling streaming. For those with large datasets who want to keep streaming, the workaround is to put an ArcGIS Web Adaptor between the reverse proxy and ArcGIS Server. Reference ArcGIS Server in ProxyPass and ProxyPassReverse with ArcGIS Web Adaptor URL.