<p>I am new in Kubernetes and stuck on the issue. I was trying to renew letsencrypt SSL certificate. But when I try to get certificate by running following command</p>
<pre><code>kubectl get certificate
</code></pre>
<p>System throwing this exception</p>
<pre><code>Error from server: conversion webhook for cert-manager.io/v1alpha2, Kind=Certificate failed: Post https://cert-manager-webhook.default.svc:443/convert?timeout=30s: x509: certificate signed by unknown authority (possibly because of &quot;x509: ECDSA verification failure&quot; while trying to verify candidate authority certificate &quot;cert-manager-webhook-ca&quot;)
</code></pre>
<p>I have checked the pods also</p>
<p><a href="https://i.stack.imgur.com/R94Wn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/R94Wn.png" alt="enter image description here" /></a></p>
<p>The &quot;cert-manager-webhook&quot; is in running state. When I check logs of this pod, I get the following response</p>
<p><a href="https://i.stack.imgur.com/BF0AR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BF0AR.png" alt="enter image description here" /></a></p>
<p>I have also tried to apply cluster-issuer after deleting it but face same issue</p>
<pre><code>kubectl apply -f cluster-issuer.yaml
</code></pre>
<p><a href="https://i.stack.imgur.com/hzNQa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hzNQa.png" alt="enter image description here" /></a></p>
<p>I also have done R&amp;D about this but could not find any suitable solution. Whats the issue here? Can someone please help me regarding this? Thanks.</p>

Hunzla Ali
<p>In my case, I was attempting to install an older version of <code>cert-manager</code> onto my cluster, and Simply pulling the latest version of <code>cert-manger</code> (1.10.1 at time of writing) and installing that worked.</p>
<hr />
<p>When attempting to install an older version of <code>cert-manager</code> I saw the following error from the <code>cainjector</code> pod.</p>
<blockquote>
<p>error registering secret controller: no matches for kind &quot;MutatingWebhookConfiguration&quot; in version &quot;admissionregistration.k8s.io/v1beta1&quot;</p>
</blockquote>
<p>I assume that the API <strong>admissionregistration.k8s.io/v1beta1</strong> has been removed between K8s versions 1.21 and 1.24, and that's why I encountered an issue.</p>
