Cant view PDF attachments

Hi!
Cant open or download PDF attachments, which has a size >2Mb. Im using Exchange account and when Im trying to open PDF attachment (>2Mb size) Outlook saying "cant download an attachment". Im really sure, that is enough space on my iPad. One more thing. When Im synchronizing mail with a native mail application, I have a same kind of error message. But when I clicked on attachment again - it had been opened with Adobe Reader.
Please fix this thing!

Nataly456 about Microsoft Outlook, v2.3.10