Please help about Woocommerce with Coursepress

I have a big problem here.
When my student buy my course and they chooses COD payment method. Coursepress automatic add them to that course (My student is not pay, but they can learn already)
Other payment method is ok, only COD method has problem.
May you please check about Courspress and Woo?
I use Woo version 2.5.5 and Coursepress Pro 1.3.
Thank you so much.