If you are getting the following error when your cart goes secure:
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Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, xxxx@xxx.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
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You may need to contact your host regarding the SSL configuration on there server. While there are many reasons why the certificate may not be working, it's most likely a mod-rewrite issue. Also, check the global https settings with your host and be sure it includes a https:// instead of a http://
