NotifyStrategy describes the retry strategy when MNS pushes messages to an endpoint and then an error occurs. MNS supports the following retry strategies. You can specify a retry strategy when subscribing to a topic:

Notification Strategy Description Parameter
Backoff retry Retry 3 times. The retry interval is a random value between 10 seconds and 20 seconds. BACKOFF_RETRY
Exponential decay retry Retry 176 times. The interval of each retry increases exponentially to 512 seconds, and the total retry time is 1 day. The specific interval of each retry is: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512 ... 512 seconds (167 512s in total) EXPONENTIAL_DECAY_RETRY