Your edge project event script is pointing at localhost for the HTTP Post, which is, unless your standard project is on the edge panel, the wrong endpoint to target. Get the IP of the standard project gateway and use that instead.
Assuming the amount of data to send is small, consider using system.util.sendMessage or system.util.sendRequest on the edge server to send a message to the main server with the data to handle. This does not require the webdev module.
Also, webdev module is not required to make HTTP requests, just to handle them.
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