Customer Service Management (CSM) module, there could be several reasons behind this issue. First, check if the user has the appropriate permissions to add attachments to the case record. In ServiceNow, permissions for creating or adding attachments are controlled by Access Control Rules (ACLs), so it’s important to verify that the user has the required access to both the Case table and the Attachment functionality. Additionally, ensure that the case record itself is in an active state, as certain business rules or conditions might prevent attachments from being added when the case is closed or in a specific state. If there are any scripts or UI policies that modify the attachment behavior, such as setting conditions on when attachments can be added, these could be interfering. Also, ensure that the Attachment Service is functioning properly in the instance, and there are no ongoing issues with the instance's file storage or server configuration that could prevent file uploads. Checking the browser console for errors or reviewing the system logs for any related issues can also provide insights into the cause of the problem. Finally, if the issue persists, it might be necessary to review any customizations that might be conflicting with the attachment process or escalate the issue to ServiceNow support for further investigation
