HTTP Request - POST - Add Attachment - Name already used

Hi everyone,

I have an issue with HTTP Request activity.
I have installed the UiPath.WebAPI.Activities version 1.7.0 as it is the most recent one that works (last release cannot make any GET call).
I have to POST invoices in a web application via an API that accept invoice details only in a xml file. When I add that xml as attachment I have to give a name (see picture below)

Whatever the name I give UiPath returns an error message saying that “There is already a parameter with the name [NotWorkingActivityShittyName]. Please use another one.”

Does anyone know what is the cause of that error ?

Thank you for your help!