If you experience the below warning message when selecting the calendar tile within MyDay then read through this article.
Error:
Symptom: No O365 events coming through but i can see events on outlook.com.
Explainsation: “email failed to retrieve data” means that there’s no data for myday to pull and push through to your calendar.
Checklist:
Ensure Oauth is checked as this would need be turned to be using modern authentication which is how myday Calendar/Mail app works.
To find this you will need to go to Control Panel > Connectors > Exchange > Edit > Tick Use OAuth Authentication for Office 365.
Steps to resolve:
One way to resolve this issue is by re-consenting on the myday office 365 app itself on Azure.
Look for the myday O365 apps in Enterprise apps and click on it.
Go to permissions and grant consent. This will reset the tokens for all users
Access Permissions - Check if the account receiving the error has a shared mailbox with multiple users. Best to check calendar permission and remove the duplicate user entry.