$ openssl s_client -connect smtp.postmarkapp.com:2525 -starttls smtp<p>Connecting to 34.249.162.51<p>CONNECTED(00000006)<p>depth=2 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert Global Root G2<p>verify return:1<p>depth=1 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=GeoTrust TLS RSA CA G1<p>verify return:1<p>depth=0 CN=<i>.postmarkapp.com<p>verify error:num=10:certificate has expired<p>notAfter=Sep 15 23:59:59 2024 GMT<p>verify return:1<p>depth=0 CN=</i>.postmarkapp.com<p>notAfter=Sep 15 23:59:59 2024 GMT<p>verify return:1<p>---<p>Certificate chain<p>0 s:CN=*.postmarkapp.com<p><pre><code> i:C=US, O=DigiCert Inc, OU=www.digicert.com, CN=GeoTrust TLS RSA CA G1
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Aug 16 00:00:00 2023 GMT; NotAfter: Sep 15 23:59:59 2024 GMT
1 s:C=US, O=DigiCert Inc, OU=www.digicert.com, CN=GeoTrust TLS RSA CA G1
i:C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert Global Root G2
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Nov 2 12:23:37 2017 GMT; NotAfter: Nov 2 12:23:37 2027 GMT
</code></pre>
Nothing on https://status.postmarkapp.com/