We do not provide technical support for using webhooks with SyncBack. Unfortunately we frequently receive requests for help using webhooks where the issue is that the webhook has not been configured correctly or the user does not understand how the webhook works.
Please contact the provider of the webhook service for help and not 2BrightSparks.
It is important to note that if you send a message, e.g. JSON, then the webhook call will be a HTTP POST. If there is no message then the webhook call will be a HTTP GET.
IMPORTANT: SyncBack V10 only uses HTTP POST regardless of there being a message or not.