CiviCRM Community Forums (archive)

One possible gotcha with ssl certs relates to the www vs no www urls.

For example my bank is tragic enough to have an ssl cert that relates specifically to www.nbnz.co.nz and look at the error I get when I go to https://nbnz.co.nz/default.aspx. Correct apache config would sort this out for them.

I don't know how it would fit with your error but maybe as a long shot try confirming the ssl cert hostname & making sure that the url you are using matches it. (e.g. try turning on the ssl setting with and without the www prefix). (If you have configured apache correctly this will be irrelevant.)