所以当我去https://example.org我明白了ERR_SSL_PROTOCOL_ERROR。我已检查了 AWS 上的安全组 (ec2/Ubuntu 16.04 服务器)，并且我确实在 TCP/HTTPS 上都打开了端口 443。我唯一启用的站点是，default-ssl.conf内容如下：
LoadModule ssl_module /usr/lib/apache2/modules/mod_ssl.so
<IfModule mod_ssl.c>
ErrorLog /var/log/apache2/ssl_engine.log
LogLevel debug
<VirtualHost _default_:443>
ServerAdmin webmaster@localhost
ServerName example.com
DocumentRoot /var/www/html
# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
# SSL Engine Switch:
# Enable/Disable SSL for this virtual host.
SSLEngine on
SSLCipherSuite HIGH
SSLProtocol all
SSLHonorCipherOrder On
# A self-signed (snakeoil) certificate can be created by installing
# the ssl-cert package. See
# /usr/share/doc/apache2/README.Debian.gz for more info.
# If both key and certificate are stored in the same file, only the
# SSLCertificateFile directive is needed.
SSLCertificateFile /etc/ssl/certs/mycert.pem #note I also tried this with a .crt file because I have both
SSLCertificateKeyFile /etc/ssl/private/mykey.key
# Server Certificate Chain:
# Point SSLCertificateChainFile at a file containing the
# concatenation of PEM encoded CA certificates which form the
# certificate chain for the server certificate. Alternatively
# the referenced file can be the same as SSLCertificateFile
# when the CA certificates are directly appended to the server
# certificate for convinience.
#SSLCertificateChainFile /etc/apache2/ssl.crt/server-ca.crt
# Certificate Authority (CA):
# Set the CA certificate verification path where to find CA
# certificates for client authentication or alternatively one
# huge file containing all of them (file must be PEM encoded)
# Note: Inside SSLCACertificatePath you need hash symlinks
# to point to the certificate files. Use the provided
# Makefile to update the hash symlinks after changes.
#SSLCACertificatePath /etc/ssl/certs/
#SSLCACertificateFile /etc/apache2/ssl.crt/ca-bundle.crt
# Certificate Revocation Lists (CRL):
# Set the CA revocation path where to find CA CRLs for client
# authentication or alternatively one huge file containing all
# of them (file must be PEM encoded)
# Note: Inside SSLCARevocationPath you need hash symlinks
# to point to the certificate files. Use the provided
# Makefile to update the hash symlinks after changes.
#SSLCARevocationPath /etc/apache2/ssl.crl/
#SSLCARevocationFile /etc/apache2/ssl.crl/ca-bundle.crl
# Client Authentication (Type):
# Client certificate verification type and depth. Types are
# none, optional, require and optional_no_ca. Depth is a
# number which specifies how deeply to verify the certificate
# issuer chain before deciding the certificate is not valid.
#SSLVerifyClient require
#SSLVerifyDepth 10
# SSL Engine Options:
# Set various options for the SSL engine.
# o FakeBasicAuth:
# Translate the client X.509 into a Basic Authorisation. This means that
# the standard Auth/DBMAuth methods can be used for access control. The
# user name is the `one line' version of the client's X.509 certificate.
# Note that no password is obtained from the user. Every entry in the user
# file needs this password: `xxj31ZMTZzkVA'.
# o ExportCertData:
# This exports two additional environment variables: SSL_CLIENT_CERT and
# SSL_SERVER_CERT. These contain the PEM-encoded certificates of the
# server (always existing) and the client (only existing when client
# authentication is used). This can be used to import the certificates
# into CGI scripts.
# o StdEnvVars:
# This exports the standard SSL/TLS related `SSL_*' environment variables.
# Per default this exportation is switched off for performance reasons,
# because the extraction step is an expensive operation and is usually
# useless for serving static content. So one usually enables the
# exportation for CGI and SSI requests only.
# o OptRenegotiate:
# This enables optimized SSL connection renegotiation handling when SSL
# directives are used in per-directory context.
#SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire
<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
</FilesMatch>
<Directory /usr/lib/cgi-bin>
SSLOptions +StdEnvVars
</Directory>
# SSL Protocol Adjustments:
# The safe and default but still SSL/TLS standard compliant shutdown
# approach is that mod_ssl sends the close notify alert but doesn't wait for
# the close notify alert from client. When you need a different shutdown
# approach you can use one of the following variables:
# o ssl-unclean-shutdown:
# This forces an unclean shutdown when the connection is closed, i.e. no
# SSL close notify alert is send or allowed to received. This violates
# the SSL/TLS standard but is needed for some brain-dead browsers. Use
# this when you receive I/O errors because of the standard approach where
# mod_ssl sends the close notify alert.
# o ssl-accurate-shutdown:
# This forces an accurate shutdown when the connection is closed, i.e. a
# SSL close notify alert is send and mod_ssl waits for the close notify
# alert of the client. This is 100% SSL/TLS standard compliant, but in
# practice often causes hanging connections with brain-dead browsers. Use
# this only for browsers where you know that their SSL implementation
# works correctly.
# Notice: Most problems of broken clients are also related to the HTTP
# keep-alive facility, so you usually additionally want to disable
# keep-alive for those clients, too. Use variable "nokeepalive" for this.
# Similarly, one has to force some clients to use HTTP/1.0 to workaround
# their broken HTTP/1.1 implementation. Use variables "downgrade-1.0" and
# "force-response-1.0" for this.
# BrowserMatch "MSIE [2-6]" \
# nokeepalive ssl-unclean-shutdown \
# downgrade-1.0 force-response-1.0
</VirtualHost>
</IfModule>
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet
截至目前/var/log/apache2/ssl_engine.log是空的。我确实这样做了，看看这是否是问题所在，但仍然没有任何内容写入。我之前在某处读到过尝试http://example.org:443，我这样做了，得到了一个 404：未找到页面，但它确实加载了，而不是收到消息This site can't provide a secure connection。我也取消了extension=mod_ssl.dllphp.ini 中的（或类似）行的注释，但无济于事。不太确定下一步该怎么做。我尝试生成新的密钥/证书组合来查看这是否是问题所在，但没有解决任何问题。还运行了 openssl 命令来检查它们是否匹配，没有收到任何错误。
我尝试过的另一件事是：sudo openssl s_client -connect localhost:443
结果：139878660703896:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:s23_clnt.c:794: