Hi @Eugene Minchenko (eminchen) ,
I understand that your app registration option is greyed out in your tenant that is linked to your MSDN subscription.
If the option to create a "new registration" is greyed out, this can happen due to a missing role on the user account that is trying to add the registration. In order to register an application in Azure AD, you need to have at least one of the following roles:
Cloud application administrator
You might also see this error if you are not registering the application on an account that has a billable tenant. Even though app registrations are free, you do need to have a credit card on file for the account if you want to create resources. See note here.
Let me know if this helps.
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