When connecting to a NetScaler in a pair, the user gets Error: "HdxSdkErrorDomain_Session error 8" when they try to start desktops. If the other NetScaler in the pair is active then the user is able to start desktops with no issues.
This is a known issue which is tracked using the issue IDÂ 0702679. A fix for this issue will be included in an upcoming NetScaler maintenance release.