It happens when you don't have a last name or everything you have is under given name. try FNU as your first name and rest in given name. otherwise you can make a request via FOIA or else call i94 dept
@Baileyjig14 were you able to get it. Because i am stuck in the same situation. Its been more than a week my application is stuck at ready to collect and i have the drop off service but i am still not getting anywhere