I have a problem in creating new connection.
It happens that when I try to create new connection to Dynamics 365 it always use my default account and it does not allow me to switch to another account.
You can change the connection by adding a new connection. After you add this new connection with the right account, it will appear in this list and you will be able to reuse it next time you create an app in PowerApp.
If you want to add a Dynamics 365 connection using a different account, you must add the connection through the Portal (web.powerapps.com).
If you are automatically logged into your default Dynamics 365 account after the authentication window launches, look for your newly added Dynamics 365 connection and click on the "Key" icon.
Please reach out to us with any futher issues you may have.
Eric, Software Engineer, PowerApps Staff