title: "The operation is insecure." On navigator.credentials.create() on firefox using Mailcow
body: <p>I'm trying to register a fido2 device in Mailcow using Firefox 95.0.2.
  When trying to do so, the Registration Status field announces:</p>
  <pre><code>The operation is insecure.
  </code></pre>
  <p>I've managed to track the error down to this line:</p>
  <pre class="lang-js prettyprint-override"><code>return navigator.credentials.create(createCredentialArgs);
  </code></pre>
  <p>Where <code>createCredentialArgs</code> is:</p>
  <pre class="lang-json prettyprint-override"><code>{&quot;publicKey&quot;:{&quot;rp&quot;:{&quot;name&quot;:&quot;WebAuthn Library&quot;,&quot;id&quot;:&quot;subdomain.domain.tld:port&quot;},&quot;authenticatorSelection&quot;:{&quot;userVerification&quot;:&quot;preferred&quot;,&quot;requireResidentKey&quot;:true},&quot;user&quot;:{&quot;id&quot;:&quot;=?BINARY?B?YWRtaW4=?=&quot;,&quot;name&quot;:&quot;admin&quot;,&quot;displayName&quot;:&quot;admin&quot;},&quot;pubKeyCredParams&quot;:[{&quot;type&quot;:&quot;public-key&quot;,&quot;alg&quot;:-7},{&quot;type&quot;:&quot;public-key&quot;,&quot;alg&quot;:-257}],&quot;attestation&quot;:&quot;direct&quot;,&quot;extensions&quot;:{&quot;exts&quot;:true},&quot;timeout&quot;:30000,&quot;challenge&quot;:&quot;=?BINARY?B?AJpcm\/8fHdnFDt60yDig2j14XLKtQmJfvslXLPIFj0g=?=&quot;,&quot;excludeCredentials&quot;:[]}}
  </code></pre>
  <p>The server uses a custom CA certificate present on the Mailcow installation, the client's host and Firefox.</p>
  <p>Any ideas on why?</p>