Webhook retries

Leanplum automatically retries webhooks that receive some error responses. Webhooks will be retried for the following HTTP error codes:

408, 409, 429, and 500 through 599.

Leanplum retries a single webhook up to 50 times, with an increasing exponential backoff starting at 1 minute in between each request (1-minute delay after the first failure, 2-minute delay after the second, 4-minute delay after the third and further retries).