I suspect that you're seeing a timeout issue and the simplest fix might be
to up the timeouts, probably at the servlet-level.
You might get some evidence that this is the issue if your log files for
the time when this happens show some unusual activity, garbage collection
is a popular reason for
We have a longstanding issue with failed to respond errors in Solr when our
coordinator is querying our Solr shards.
To elaborate further... we're using the built-in distributed capabilities of
Solr 3.6, and using Jetty as our server. Occasionally, we will have a query
fail due to an error
