Why Dinpay keep sending notification?

Reason:
In this case, sometimes the order, certain orders will update successfully, sometimes some will fail on merchant website.
This is due to the program in notification page file (parameter notify_url corresponding page file) throws an exception during execution, resulting Dinpay service couldn’t receive the SUCCESS character send by merchant.
How to check:
Check server asynchronous notification page (parameter notify_url corresponding page file)
Step 1: Check notify_url page file
A. Merchant and Private Key are filled in correctly, not space is required
B. notify_url path is accessible on internet, ensure the page is not blank or no error message prompt by the software itself
C. Request parameter show_url, return_url, notify_url should not consist of self-defined parameter, such as:
http://www.xxx.com/return_url.asp?id=123?id=123,the parameter follow after “?” is self-defined parameter.
D. Check the coding format
Coding format error. May use log function (log_result) to record data in Chinese to check whether there is any messy code. If there is messy code, it is due to different coding format setting. Check the coding format parameter input-charset, webpage attribute code, overall code for web application, etc. ensure no messy code when transmitting data.
E. In notify_url page, only enter SUCCESS and ensure the page is entirely blank without any HTML label, space, crlf and other character.
SUCCESS code for different programming language:
ASP.NET:Response.Write("SUCCESS");
ASP:response.write "SUCCESS"
PHP:echo "SUCCESS";
JAVA:out.println("SUCCESS");
F. No seesion or cookies should include in notify_url page, do not auto redirect page