It looks like https://<your organization name>.crm.dynamics.com
E.g.: https://mage2.crm.dynamics.com in my case.
You can find out your exact URL in the Dynamics 365 Administration Center:


It looks like https://<your organization name>.crm.dynamics.com
E.g.: https://mage2.crm.dynamics.com in my case.
You can find out your exact URL in the Dynamics 365 Administration Center:

