Cannot upload pdf file

Hi..Im not sure this site buggy or something but currently I cannot upload pdf file for client review the design.

It's says " File type error".

I have multiple design to show to the client and the quickest way to do this is combine the multiple jpeg into single pdf file..

Before this it work fine..

And sometimes the "#" tag cannot preview the design as it should..

Btw..it happen in the finalization stage..

Maximum image size is 4Mb for the contest (I think that is also finalizing).
Why pdf, where you can jpg, png ....

Please upload a jpg or png file if you are showing images in finalization otherwise upload  a new zipped source files and include the pdf there

Thnak you