This is the first time you have posted a question. So you should tell us more about what the actual issue is. For example, tell us the behavior that you are experiencing from the plugin and on which page? So we have more details and reference to try to understand what could be causing the issue.
Did you enable or disable custom fields in the individual product configuration?
Normally, custom fields related issue are configuration related. So it is a good idea to read through the following documentation couple of times to make sure you haven’t missed a step: