I suggest opening a JTAC case instead of posting here if this is critical.
However, you could have started with "hello everyone, does somebody already had this kind of issue and is able to help me please?"
Maybe you could precise if this is a new setup, a change in your configuration (SA/Proxy/both/none)?
In very latests version there is a bug if you use "auto detect proxy" settings in IE, but affects only Secure Meeting/COllaboration suite I guess. What is your proxy configuration? You could try to exclude SA hostname from your proxy pax configuration?