Setting up master account for power bi embed

[powerbiEmbeUser]

I am trying to implement the App owns data where we use a master account with Pro lisence to authenticate and fetch power bi embed codes and integrate that in the web app. These are the things I did so far

1. Create a new native application in Azure AD

2. Authenticating the user using ADAL from C# using the credentials of the master account with power BI Pro embedded within the application.

The above steps are without explicit grant permission in the app.

Now when I do this I  get an error like "AADSTS65001: The user or administrator has not consented to use the application with ID '' named ''. Send an interactive authorization request for this user and resource"

Which looks like we haven't consented the app to authenticate on behalf. 

The issue is our global admin doens't want to Grant consent for all users. 

From register app, "The Grant Consent action needs for the master account to avoid being prompted for consent by Azure AD. If the account performing this action is a Global Admin, you grant permissions to all users within your organization for this application. If the account performing this action is the master account and isn't a Global Admin, you grant permissions only to the master accountfor this application.". It says the master account can grant consent for the app. But I'm not sure how to get this done. 

From creating azure docs I can see that the user with Directory role as "User" is the master user. So I should be able to grant consent from my master account itself, right?

Also, how can a global admin give consent only for a master user? since all the calls to power BI REST will be through the master user.

Update

I just realized the admin consent is already granted yet I'm seeing this message. This is how the permission for the app looks like 

[veasnamuch]

Dear Friend,

Do you manage to get it works? I have face the same issue like yours. Would you mind to share, how to make things works? 

Best regards,

Veasna