The subscription (based on DUMMYGATE service template with cancellation set to manual) was cancelled, Cancellation order placed, an appropriate record appear in the Manual Operations list, but completing it does not take any effect, the order is still in MO (Manual Operation required) status.
Check for an error in the
One of possible errors is
"Can not apply Cancellation Order Item for 'Running' Service of Subscription."
The subscription was not stopped on cancellation order placement. Check if the handler StopSubscription is assigned to an event "Cancellation Order Placed":
Home > System > Settings > Events > Event Types > Event Type Cancellation Order Placed Event Handlers
To avoid issue from reoccurring - add it for the subscription to be stopped on cancellation order placement. To provision a current order, stop the subscription manually (possible by putting the subscription on the administrative hold for example) and complete a manual operation.
It is also possible that service stopping is set to manual in the same DUMMYGATE service template and you attempted to complete a cancellation process before stopping. In this case it is required to stop a service at first (complete an operation to stop service for a subscription from the Manual Operations list) and only then complete a cancellation. The absence of any comprehensive notices on attempt to complete cancellation before stopping is considered as a bug with id #PBA-60480 ("We can't complete cancellation order"), fixed in BA 7.0.