Voice for Dynamics 365 is an embedded CCaaS solution. Use your CRM as a contact center without separate voice channels. All customer data is stored in one place to create a 360-degree customer view.
...
Standard authentication
Simple for the end-user, but less secure.
No special actions are needed from you, the phone logs in seamlessly.
Modern authentication
...
Slightly more complex for the end user, but also more secureEnables customer to use modern authentication method. Typically customer company's own Microsoft work credentials (AzureAD) with single-sign on experience.
Instead of the phone getting logged in automatically, you might be facing the message on the screenshot.
...
The role can be found in: Advanced Settings → Security → Users or Teams, to be assigned for the D365 user.
...