You need to choose a user attribute to store user’s alternate email in user properties while configuring netscaler SSPR.
You’ve chosen a user attribute which is not in use, and configured netscaler SSPR. User, when logging in for the first time to netscaler gateway url, got questions to fill and enter alternate email id page after entering credentials. Immediately, they get an error “System error” and will be returned back to username and password page.
What happened behind scenes is, Netscaler showed the questions you selected. When it tried to save it to the user attribute you selected, it is not able to write to that attribute. So, got a system error.
Change user attribute to “userParameters”. In your AD servers, enter same “userParameters” in KB Attribute and Alternate Email columns. Login to your netscaler gateway url. When you see questions, fill all the answers and enter alternate email as well. Goto the user properties in AD, and check if “userParameters” attribute has a value. This means netscaler is able to take your details and update the user attribute successfully.