We had similar issues with ios devices. It seems to be related to making sure their is a default email application tied to the default applications for email on the ios device. In our case, with thousands of devices that would need that option updated to work we decided to just make it a pop up message with the email address they should send the email to. The user then would have to copy and paste it. Not optimum but until we can make sure all ios devices are set up correctly this email action will not work.
If you come up with another solution please share. Thanks!