Exchange email issue

[renscoulier]

Hi all,

We are using the new P9's for our company and some users are complaining about the following:

they receive a notification that they have a new mail, but when opening the mail app it's not showing.
Rebooting the device, disabling/enabling wifi/4G doesn't matter. Only after a certain time they suddenly get all their emails in one go.

Anyone else had this issue?
ifso, what can be done to fix it?

Thanks,
Rens