I am new on this forum and I search for a while before posting this question.
I am helping a company configuring an ((OTRS)) install (6.0.12) which was updated from 3.1.7.
When a customer is creating a new ticket with an attachment, the agent receives an email. Unfortunately, the attachment is not part of the email. There is a link to open the ticket in the backend - which I find is good enough. But the support agents were used to have the attachment in the email and want this to be working again. I have checked with different file sizes, it is not a matter of size (not this time

I have played with the AttachmentDownloadType module inline/attachment, but that didn't help.
So the question is: is it possible to have attachments on the emails using ((OTRS)) out of the box? And if yes, what might I be missing?
Thank you for help and hints
Littlebuddha