Intermittent "Page can not be displayed" errors on SSL sites
It is a known issue of mod_ssl, see the related mod_ssl FAQ below.


The first reason is that the SSL implementation in some MSIE versions has 
some subtle bugs related to the HTTP keep-alive facility and the SSL close 
notify alerts on socket connection close. Additionally the interaction 
between SSL and HTTP/1.1 features are problematic with some MSIE versions, 
too. You've to work-around these problems by forcing 
Apache+mod_ssl+OpenSSL to not use HTTP/1.1, keep-alive connections or 
sending the SSL close notify messages to MSIE clients. This can be done by 
using the following directive in your SSL-aware virtual host section: 

    SetEnvIf User-Agent ".*MSIE.*" \
             nokeepalive ssl-unclean-shutdown \
             downgrade-1.0 force-response-1.0
             
Additionally it is known some MSIE versions have also problems with 
particular ciphers. Unfortunately one cannot workaround these bugs only 
for those MSIE particular clients, because the ciphers are already used in 
the SSL handshake phase. So a MSIE-specific SetEnvIf doesn't work to solve 
these problems. Instead one has to do more drastic adjustments to the 
global parameters. But before you decide to do this, make sure your 
clients really have problems. If not, do not do this, because it affects 
all(!) your clients, i.e., also your non-MSIE clients. 
The next problem is that 56bit export versions of MSIE 5.x browsers have a 
broken SSLv3 implementation which badly interacts with OpenSSL versions 
greater than 0.9.4. You can either accept this and force your clients to 
upgrade their browsers, or you downgrade to OpenSSL 0.9.4 (hmmm), or you 
can decide to workaround it by accepting the drawback that your workaround 
will horribly affect also other browsers: 

    SSLProtocol all -SSLv3
    
This completely disables the SSLv3 protocol and lets those browsers work. 
But usually this is an even less acceptable workaround. A more reasonable 
workaround is to address the problem more closely and disable only the 
ciphers which cause trouble. 
    SSLCipherSuite \
ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP

This also lets the broken MSIE versions work, but only removes the newer 
56bit TLS ciphers. 
Another problem with MSIE 5.x clients is that they refuse to connect to 
URLs of the form https://12.34.56.78/ (IP-addresses are used instead of 
the hostname), if the server is using the Server Gated Cryptography (SGC) 
facility. This can only be avoided by using the fully qualified domain 
name (FQDN) of the website in hyperlinks instead, because MSIE 5.x has an 
error in the way it handles the SGC negotiat