1. Confirm whether your digital signature has expired. If it expires, please re-apply for digital signature. 2. The merchant signature ID of the website you are using has expired. Contact the website to solve this problem. 3. The client can't verify the digital signature due to the failure of CITIC Bank's server. 4. Close the transaction page and log in to CITIC Bank again to see if the fault has been eliminated. 5. Clear the browser cache. 6. Check whether the browser disables page Javascript, if so. 7. The long transaction cycle may be a problem with the page script. If it is IE7 or later, please enable Page Compatibility View 8. After submitting the transaction information, wait for the page to respond. Don't refresh the page, or you will always submit this single number, and the customer single number given by the bank server is unique every time. This problem will occur after the expiration. If it is a problem after refreshing, please check whether there is a problem with your digital signature, and then follow step 4 to solve the problem.