Sometimes I get an email with the following. I believe it's being caused by our Zendesk integration, but I've checked over the settings and it seems to all be fine.
An error was encountered upon synchronizing Issue: DROID-824.
Below are the errors:
Error updating remote object, caused by. Error status 406:<?xml version="1.0" encoding="UTF-8"?>
<errors>
<error>Status closed prevents ticket update</error>
</errors>
These errors are also logged in the Diagnostics section in the Administration Console.