Sporadic "connection refused" errors from Subversion hosted in Apache

We have a Subversion server hosted in Apache on Windows that's been running fine for years. Recently clients have started seeing sporadic "connection refused" errors. Retry开发者_StackOverflowing the operation will work - it seems fairly random about when it will fail or not.

Nothing jumps out at me in the Apache error.log. What can I do to diagnose this further?

Have the affected users disable their virus scanners and see if the problem persists. I've received similar reports and both times this fixed their issues.