1. What nop version do you use?
2. Do you use Linux or Windows hosting?
1. Upgrade the plugin and use the last release
2. Open the plugin configure page and enable debugging.
3. When you see the same issue you need to send me the plugin log file and check the nopcommerce log.
Do you use the nopcommerce checkout or checkout from external developers?
I didn't get any emails
I wrote to you myself
Please resend it
I found very old email at Jun 16.