Wikimedia Bugzilla is closed!

[originally reported on wikitech]

An error message that happens frequently during editing, more frequently during peak hours. 
Sometimes the post goes through (but is not visible without purge of the page), other 
times a new post is required.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request POST /wikipedia/en/w/index.php.

Reason: Error reading from remote server

===

I get a similar error (sometimes) on Preview or (rarely) just reading a page:

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /wikipedia/en/wiki/Wikipedia talk:Biographies of living persons.

Reason: Error reading from remote server