I have two AWS servers in the Singapore region that cannot access acme-v02.api.letsencrypt.org. They report the following errors:
$ openssl s_client -connect acme-v02.api.letsencrypt.org:443 -showcerts
CONNECTED(00000003)
write:errno=104
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 320 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---
$ curl -sv https://acme-v02.api.letsencrypt.org
* Trying 172.65.32.248:443...
* TCP_NODELAY set
* Connected to acme-v02.api.letsencrypt.org (172.65.32.248) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* OpenSSL SSL_connect: Connection reset by peer in connection to acme-v02.api.letsencrypt.org:443
* Closing connection 0
The IP addresses of the two servers are: 54.255.55.25 and 18.138.237.72. Are they blocked?