Entry SYNCH does not exist in SWN_DELSCHED

Hello,

Extended Notification which will send email automatically to outlook (based on user's mail id in SU01D) whenever the approver receives new approval task and the email will have link to Approve/Reject (based on the underlying WF step). When approver clicks on the link, it will ask for user id/pwd and approver can take decision

While Subscription Basic data setup getting below error;

Entry SYNCH   does not exist in SWN_DELSCHED (check entry)

Message No. 00058

Thanks

mahesh