1. Browser compatibility issues: Some signature controls may require a specific version of the browser or plug-in to work properly. If you are using an unsupported browser or an outdated plug-in, the signed control may not be displayed or run.
2. Signature control is not installed correctly: You may need to install signature control on your computer to work properly. If you don't install the signature control correctly, it may not be detected or loaded by the online banking system.
3. Security settings restrictions: Some security settings or antivirus software may prevent the signature control from running normally. These settings may prevent browsers from loading or executing controls to protect your computer. You can check your security settings or temporarily disable anti-virus software to see if it can solve the problem.
4. Problems with the online banking system: Sometimes, the online banking system itself may have problems or be under maintenance, which makes it impossible to display the signature control. In this case, you can try to log in to the online banking system again later, or contact the bank customer service for more information.