Looks like when we configure the REST API in Gerrit trigger plugin, it will be used +implicitly +over SSH to send notifications back to Gerrit.
This also implies that the user used for REST API configuration should have access to Gerrit repositories.
When "user A" is used for stream events and "user B" is configured in REST API, we will have errors sending back the notification in case "user B" does not have access to Gerrit repos.
Today REST API section is missing the helper section. Please create the Helper section and mention this information over there.