This could be intermittent server issues on the external service.
Handle errors so scenarios don’t stop
You might want to add some error handling to your modules to handle exceptions, so the failing module(s) can automatically be ignored or retried after a short period. By handling any errors by adding a “Error handler” to the module, the scenario won’t throw errors and get switched off.
Error directives can only be added to an error handler route
1. Right click a module and select “Add error handler”
This is Meta’s error, not Make’s. Error code [400] is Meta saying their API is overloaded or temporarily down on their end. It’s not your configuration. It’s Meta’s infrastructure.