Ah! Ok, I think you need to add the intermediate certificate[1] that chains the Let&#x27;s Encrypt Authority X1 to the IdenTrust root. Here&#x27;s instructions on how to do this for nginx: <a href="https:&#x2F;&#x2F;github.com&#x2F;diafygi&#x2F;letsencrypt-nosudo#how-to-use-the-signed-https-certificate" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;diafygi&#x2F;letsencrypt-nosudo#how-to-use-the...</a><p>[1]: <a href="https:&#x2F;&#x2F;letsencrypt.org&#x2F;certs&#x2F;lets-encrypt-x1-cross-signed.pem.txt" rel="nofollow">https:&#x2F;&#x2F;letsencrypt.org&#x2F;certs&#x2F;lets-encrypt-x1-cross-signed.p...</a>