Hi, tx for answering !
Because of several reasons I would like to track this down with the "Security" of the company. The only difference in the emails coming through or not was the generator for the PDF attachments:
- I successfullx sent frequently PDFs created with Ghost to this customer
- I changed to doPDF (much mor convenient & better colors in PDF)
and could not get the stuff through the wall
- I changed back to GS and got the same mail through 5 minutes after
So: The only difference was the Software creating the attached files. Nothing changed in size, names & attachments of the emails coming (not) through. I assume, something within the "PDF-code" is different & suspicious for supercritical Wall/Filters.