We are trying to attach a file through Message Center template. With files hosted on public URL is working fine but we want to attach documents(pdf's) hosted on secure URL ( i.e. Basic Auth). Is there way to inject auth header , when MTA tries to read the remote file.
If you host the file on the message center server instead of on Public URL, you can get the attachment processed and see if we have the type of authentication needed? as far as I know, authentication of any type is not supported in the campaign classic message center module.