While trying to add a new Trial (subscription-based) on a Dynamics 365 Trial environment, we were getting the below error
Currently, Dynamics 365 apps can only be enabled for your default region
The default region was UAE for the other environments
Even for the Azure Synapse Link – it was showing the default region as UAE North
In our case selecting the Region to Europe allowed us to create a Trial (subscription-based).
Get all the details here – https://docs.microsoft.com/en-us/power-platform/admin/create-environment
Hope it helps..