Symptoms

The following appears in the IE browser when trying to access the indexing page from Confluence Admin >> Content Indexing:

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /admin/search-indexes.action.
Reason: Error reading from remote server
Apache/2.2.15 (CentOS) Server at confluence.com Port 80

Cause

This error message triggered when an SSL connection is configured from the browser to Apache, and Apache does a reverse proxy to your Tomcat server. Internet Explorer sends the wrong host information in an SSL connection and confuses Apache VirtualHosts.

In short, the server name presented is that of the reverse DNS resolution of the IP, not the one in the URL.

Workaround

There are three workarounds for this issue:

1. Remove the reverse proxy

2. Make a configuration where there's only one IP address per SSL virtual hosts/server name

   1 server name == 1 IP address == 1 certificate == 1 Apache Virtual Host

3. Use a different browser

References:

• Server Name Indication