我在端口 443 上有一个 OpenVPN 服务器。我无法连接到该 OpenVPN 服务器：
Thu Oct 13 10:11:39 2022 TLS Error: TLS handshake failed
Thu Oct 13 10:11:39 2022 Fatal TLS error (check_tls_errors_co), restarting
Thu Oct 13 10:11:39 2022 SIGUSR1[soft,tls-error] received, process restarting
OpenVPN 已启动并运行，并且端口 443 已开放：
[mehrdad@rock ~]$ sudo nmap -sS -O -p80,443 <the-server-ip>
Starting Nmap 7.70 ( https://nmap.org ) at 2022-10-13 15:04 +0330
Nmap scan report for <the-server-ip>
Host is up (0.13s latency).
PORT STATE SERVICE
80/tcp closed http
443/tcp open https
我怀疑 ISP 阻止了 SSL 连接。我该如何测试这个？
以下是什么意思？
[mehrdad@rock ~]$ openssl s_client -connect <server-ip>:443
CONNECTED(00000003)
write:errno=0
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 293 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)