[Hustle] issue with custom theme

On my site https://***.org/ when you click on SIGN UP button in footer section the pop up appear, but X close does not close the pop up.

During the chat w try plugin conflict and we upgrade Hustle to new version but this does not help.

I got a custom theme and this is a live site so I could not test theme conflict.

Can you check this on my staging site I prepare?

Thank you