Attach pdf file timeout

.. sounds like you need a support ticket.  They did move data centers over the weekend and that sounds suspiciously like "in the last 1-2 days" where you feel that there is a problem.  I uploaded a 7 MB file yesterday - actually the same file 6 times  and it uploaded fine, although for the first time I did see a counter showing the count of the progress.  At the time I just attributed that to it being an unusually large file.

I have done as you suggested and created a case.
Thanks for your help.

I had the same issue today, choked and times out on a pretty average file.