PDF invoice for WP ERP not working

Hi,

I am using “PDF invoice for WP ERP” with wp erp plugin and I am getting following issues:

1. before installing “pdf invoice for wp erp” whenever I create invoice there will be a confirmation message “created successfully” but after installing “pdf invoice for wp erp” message appears is “could not create invoice” but after disappearing message entry created. This means wrong message appears.
   you can see image here
2. After clicking “more action > export as pdf” there is no pdf file is created. Directory “uploads/erp-pdfs/” were empty.
3. After clicking on second option “Send Mail” a popup appears but after clicking on send button there is no any action after submitting to, subject, message, attachment fields.
   you can see image here

Kindly tell me what is the problem

I am using wp erp version 1.12.9

WP ERP – PDF Invoice version 1.2.1

wordpress Version 6.4.2