That usually means that you did not correlate all the dynamic parameters. Before running a test with 10 Vusers have you run a check virtual user to make sure that it's working fine?

You should run a test in debug mode and configured at the scenario level to store all the user interations. That way you will be able to troubleshoot the user iterations that did not work.

This is a link from the NeoLoad documentation here

The last section is related to debug mode. Then start your test hitting the "debug" button instead of the regular play button.

You will get the user iterations result under test Results section under "Details" tab.