Report Subscriptions are not working. I cannot modify them too. Why?

Report Subscriptions are not working. I cannot modify them too. Why?

If a particular KPI or a list of KPIs are selected as part of the report subscription, has undergone a change w.r.t its original KPI configuration (for e.g., either a measure used in the KPI is modified/delete) then, the report subscription will not work even though the individual KPI will work as expected. It is suggested that you to delete all these problematic reports and have them recreated.