Are you using Opencart 2.0 or Opencart 2.1 with SSL (HTTPs), then you may getting error (like: error undefined) while editing orders in your admin dashboard. So, here is the solution for that error.
- Fix HTTPs in Admin Orders
- Supports both VQMOD & OCMOD
- No File Replacement
This Modification is only for Opencart 2.0 and opencart 2.1 because later on Opencart fix this problem in version Opencart 2.2