If you are seeing the generic error page for nopCommerce and are unsure how to debug the issue please see below to find the true error.
When the generic error page is shown you need to know what the true error is before resolving it. You have two options.
1. Open the administration by navigating to YourStoreName.com/admin and then go to System > Log.
The Log contains all the errors and warnings in your store. Most of the time you should be looking for the most recent error. The error details contain all the information you need to investigate and fix the problem.
2. If you can't access the administration you have to turn off the custom errors, so that you are not navigated to the Error Page. To do so, modify your Web.config file by replacing RemoteOnly with Off:
<customErrors defaultRedirect="errorpage.htm" mode="RemoteOnly">
change to:
<customErrors defaultRedirect="errorpage.htm" mode="Off">
The true error will now show when you view the website.
Feel free to contact support if you have any issues with this.
There are also a lot of good guides here to help nopCommerce administrators handle various issues:
https://docs.nopcommerce.com/user-guide/installing/faq.html
