SYMPTOMS

Uploading attachments larger than 30000Kb fails via Outlook 2013 when sending via EAS (ActiveSync).

CAUSE

The IIS web server imposes a restriction that is preventing content length requests greater than 30Mb.

RESOLUTION

1. Open IIS (Internet Information Services Manager).
2. Click on the root IIS node.
3. Within the Root IIS Home options window double click on "Configuration Editor"
   Use the "Section" dropdown menu and navigate to: system.webServer/security/requestFiltering
4. Expand "requestLimits" and edit the value for "maxAllowedContentLength" to 2000000000 (2Gb)
5. Click "Apply" in the "Actions" pane
6. Restart IIS

MORE INFORMATION

https://msdn.microsoft.com/en-us/library/ms689462%28v=vs.90%29.aspx?f=255&MSPPError=-2147217396