Hi Aladdin,
Thanks for contacting Syncfusion support.
If the server-side events are not working fine, we suspect that you have not referred ej.webform.min.js file and ScriptManager Control in the Project. So, please ensure that you have referred both the files in your project.
For more information, refer to the below Knowledge Base document.
If you still face the same issue, we need the following details
1. Code example.
2. Did you face the issue after upgrading to new version?
3. Current version of the Syncfusion control.
Regards,
Prasanna Kumar N.S.V