“Sorry, something went wrong while initializing the app.” when accessing the Dynamics 365 App for Outlook

When you click the Dynamics 365 app in Outlook (anywhere the app is supported) and your Dynamics 365 (online) instance is version 9.x, you see the following message:

“Sorry, something went wrong while initializing the app. Please try again, or restart the app”

When you click View More, you see the following additional details:

"Error: AppforOutlookModule was not found, empty appId returned Trace: Error: AppforOutlookModule was not found, empty appId returned at ..."

This can occur if you have a custom Dynamics 365 security role assigned and the role does not have access to the Dynamics 365 App for Outlook app module.

If you are using a custom security role, refer to the following documentation for how to grant the role access to the Dynamics 365 App for Outlook app module:

https://docs.microsoft.com/dynamics365/customer-engagement/outlook-app/deploy-dynamics-365-app-for-outlook#provide-security-role-access

After verifying all required privileges, close and reopen Outlook.