Fix sync issues with mobile devices
If you're having trouble receiving or sending messages from your mobile device, try removing the device in Outlook.com options.
Go to Mobile devices.
In the list of connected mobile devices, select your phone, and then select Remove.
Remove phone from Outlook Web App
Select Yes in the confirmation box.
Go to your mobile device and power it off completely.
Restart your mobile device after a few seconds, and then sync your mailbox again.