SBMI recommends that students use Firefox, IE, or Safari to access UTH Webmail.

UTH students are not able to send emails with attachments using UTH webmail with Chrome at this time. This is due to the technical limitations of the Chrome browser. Chrome may not support certain features of Webmail (Exchange 2010).

Here is an article that provides the technical details:
http://blog.chromium.org/2014/07/disabling-showmodaldialog.html