Problem viewing sites with SSL certs

Question

I am managing a number of websites that use SSL certificates and have had a few complaints from individuals that are not able to view some of these sites in secure mode. The problem persists regardless of browser or version that is used, does not affect viewing in non-secure mode, and only occurs with a few of the secure sites, not all. Each site has a separate SSL certificate.

I don't have any idea what may be causing this problem or how to address it and would appreciate any helpful questions or ideas that would contribute to fixing it.

Answer 1

Maybe they are behind some proxy that is performing interesting operations of SSL connections?

Answer 2

Just a hunch, but one possibility could be that weak ciphers are disabled on the server and strong ciphers are not enabled on the client. Another possibility might be that the root certificates list on the client is not up-to-date and the SSL certificate is signed by an authority that is not in the trusted list.

Answer 3

They key here is to find out what they all have in common. Maybe they all use AOL? Behind a caching proxy? Can they view other secure sites? Maybe they have a virus or trojan causing the issue?