Microsoft have announced they will be retiring the Microsoft OWA mobile apps. Some people use these apps for accessing their emails on mobile phones or tablets. If you are one of them then you need to move to the more up-to-date and feature rich Outlook for iOS or Outlook for Android.
The OWA apps will disappear from the iOS and Android stores in April 2018 and they will stop working completely by 15th May 2018. If you require any assistance in removing the old apps or installing the new apps then please speak to your IT Technician who will be able to help.