Missing sessions, session users, and overall slow performance of GPM can be caused by user data exceeding 10MB. This will cause Goliath to start ignoring the sessions for that specific user as well as making the GPM web console inaccessible. Looking into IIS, you can check for the maximum length of content, URL, and query string and increase those values in order to resolve the issue.
- Open up IIS
- Double click on the Goliath user
- Go into the sites folder
- Go to the GoliathWeb dropdown
- Click on "Agent"
- On this page double click on "Request Filtering"
- On this page under the "Actions" tab on the right side click on "Edit Feature Settings"
- In the pop-up window, "Edit Request Filtering Settings", change all of the Maximum lengths to 4294967295.