uration in <code>DestinationRule</code>.</li><li><code>UF</code>: Failed to connect to upstream, if you&rsquo;re using Istio authentication, check for a
<a href=#503-errors-after-setting-destination-rule>mutual TLS configuration conflict</a>.</li></ul><p>A request is rejected by Mixer if the response flag is <code>UAEX</code> and the Mixer policy status is not <code>-</code>.</p><p>Common Mixer policy statuses are:</p><ul><li><code>UNAVAILABLE</code>: Envoy cannot connect to Mixer and the policy is configur