https://support.huaweicloud.com/intl/tr-tr/usermanual-smn/smn_ug_0010.html
Canceling a Subscription_Subscription Management_User Guide_Simple Message Notification-Huawei Cloud
After you add subscriptions to a topic, the subscribers receive a confirmation message and need to confirm their subscriptions to receive notification messages...
simple message notificationsubscription managementuser guidehuawei cloudcanceling